my usb stick was containing som kind of virus which was visible and my little brother double clicked on it! and now my laptop is infected!! the virus opens several Firefox tabs and opens some websites as advertisement! the virus does this every 20 minutes whether the browser is open or not!! and it is driving me crazy. I dont know how to prevent it from opening tabs :(     I checked and there is no unwanted add-on or plugin on my browser! should I delete my browser?
What should I do if my Windows computer seems to be infected with a virus or malware?  What are the symptoms of an infection? What should I do after noticing an infection? What can I do to get rid of it? how to prevent from infection by malware?   This question comes up frequently, and the suggested solutions are usually the same. This community wiki is an attempt to serve as the definitive, most comprehensive answer possible. Feel free to add your contributions via edits.
I just finished installing mysql-server, and then installed phpmyadmin which came with Apache and PHP. It set it up alright and made a phpMyAdmin database, but I can't seem to find the URL to get to it -- I tried going to  but it doesn't seem to be there.  I can't find the location in any of the manuals, does anyone know where this is located? Thanks. How much effect does the Bernoulli effect have on lift? I understand that the Bernoulli effect is a flawed explanation for the cause of lift, and does not cause much at all, but how much?   Is there any experimental data on the force caused by the Bernoulli effect? Maybe implicitly through data of the pressure difference between the top and underside of an aeroplane's wings. After that, I assume I could (crudely approximating the pressure to be acting perpendicularly to the flight direction) use $\Delta P A$ to work out the net force on the plane.    Perhaps there is another way to quantitatively analyse the extent to which the Bernoulli effect causes lift.  Edit: see  short cartoon (content similar to Mike Dunlavey's answer). Colored borders around windows after update Compute $\sum_{n=1}^\infty \frac{1}{(n+1)\sqrt[]{n}+n\sqrt[]{n+1}}$ Compute   $\sum_{n=1}^\infty \frac{1}{(n+1)\sqrt[]{n}+n\sqrt[]{n+1}}$ 3D graphics render as though no illumination Are spells learned from feats considered to be associated with your class? The multiclassing spellcasting rules (PHB p. 164, or ) state:  Each spell you know and prepare is associated with one of your classes, and you use the spellcasting ability of that class when you cast the spell.  According to the above, every spell you know or prepare should be associated with a class.  However, for spells learned from feats like Drow High Magic or Wood Elf Magic are these actually associated with a class? If so, what class? If not, is the PHB statement above wrong/outdated? Are the spells learned in these feats (and others like it) associated with something else (like your race, in these cases)?  For reference, the  racial feat (XGtE p. 74) states:  You learn more of the magic typical of dark elves. You learn the detect magic spell and can cast it at will, without expending a spell slot. You also learn levitate and dispel magic, each of which you can cast once without expending a spell slot. You regain the ability to cast those two spells in this way when you finish a long rest. Charisma is your spellcasting ability for all three spells.  The  racial feat (XGtE p. 75) states:  You learn the magic of the primeval woods, which are revered and protected by your people. You learn one druid cantrip of your choice. You also learn the longstrider and pass without trace spells, each of which you can cast once without expending a spell slot. You regain the ability to cast these two spells in this way when you finish a long rest. Wisdom is your spellcasting ability for all three spells.  In regards to the third and fourth questions, the fact that the PHB quote says &quot;use the spellcasting ability of that class when you cast the spell&quot; and the fact that the feats specify what ability the spell uses in these examples (independent of class) suggests to me that they are not associated with class. I'm trying to create a functioning sub theme of Omega 4.4. I've worked  with Drush before with it, but the site is on a host that I'm not administrator of. I've tried the  but not succeeded in executing the Omega Wizard. In short, the Omega Wizard may be extremely helpful, but I can't get it to work.   Next, I've tried to manually create a sub theme using the . However, the results of this is a theme catalogue in the Themes-folder, but the theme not showing up in Drupal. Perhaps I'm using the wrong instructions for the wrong version of Omega?  Anyhow, does anyone have instructions for how to install an Omega 4.4 sub theme manually for Drupal 7? Linear algebra is a very well-behaved part of mathematics. Soon after you have mastered the basics you got a good feeling for what kind of statements should be true -- even if you are not familiar with all major results and counterexamples.  If one replaces the underlying field by a ring, and therefore looks at modules, things become more tricky. Many pathologies occur that one maybe would not expect coming from linear algebra.  I am looking for a list of such pathologies where modules behave differently than vector spaces. This list should not only be a list of statements but all phenomena should be illustrated by an example.  To start the list I will post an answer below with all pathologies that I know from the top of my head. This should also explain better what kind of list I have in mind. Is there a way to input particular sections of source code using \lstinputlisting (from the listings package) in a flexible way?  It's possible to use the firstline and lastline options to input particular line ranges, but this isn't robust to changes to the source file.  For example, suppose that the input source file is:  int square(int x) {   return x * x; }  int cube(int x) {   return x * x * x; }   In my LaTeX document, I can include the cube procedure using the command \lstinputlisting[firstline=5,lastline=7]{source.c}.  But suppose I later decide to rewrite the cube procedure.  The input source file becomes:  int square(int x) {   return x * x; }  int cube(int x) {   int x2;   x2 = square(x);   return x * x2; }   Now my LaTeX document will not show the final two lines of cube because the listing uses only lines 5-7.  I could manually update the line range, but this is tedious and error-prone.  Is there a way to mark sections of source code with some kind of label so that the listing will be robust to these sorts of changes?  For instance, perhaps the input source file would be something like  int square(int x) {   return x * x; }  /**\beginlabel{lst:cube} **/ int cube(int x) {   int x2;   x2 = square(x);   return x * x2; } /**\endlabel{lst:cube} **/   so that I could use something like \lstinputlisting[lines=lst:cube]{source.c} to include the section that I want and remain robust to changes.  I am open to using other packages for source code listings (e.g., minted) if helpful. Why is "glide symmetry" its own type? Artin's Algebra pages 155 &amp; 156 list the types of symmetry of a plane figure as:   Reflective Rotational Translational Glide   He then goes on to say "Figures such as wallpaper patterns may have two talk about other figures having combinations of independent" symmetries. EDIT: He says "... having combinations of independent translational symmetries". See Joriki's answer.  Why doesn't glide symmetry count as having two independent (reflection + translation) symmetries? If we're going to count combinations, why not have rotation + translation etc. as their own types too? I have two machines with RJ11 ports and I had a RJ11 Modular Telephone Cable lying around.I wondered if it was possible to create a network between the two machines with those RJ11 Modular Telephone Cable (back to back via RJ11 ports) much like a network we create between two computers with a single RJ45 Modular connector cable.  Is this setup possible at all ? If it is , what will be the maximum transfer speed i can achieve between these two computers ? The vote fraud script breaks legitimate polling questions - A serial downvoter's lament I've downvoted several of the answers on these Meta discussions:       Both questions are typical self evaluations, Stack Exchange runs them on all young Beta sites and as you may have noticed they are essentially polls, a series of example questions from the site that we are supposed to vote on.  Today I noticed that almost all of my votes have disappeared on both evaluations, only an upvote remains in the later one. My votes triggered the serial voting script, something that :      Heh, it appears I just serially downvoted you (I downvoted a lot of the answers here), hopefully the script is smart enough to not reverse my votes. Will check back in 24h, and if it does, I'll rant about it on MSO ;)    My voting behaviour on both evaluations was very simple:   I had the evaluation open in the left monitor, Opened all the example questions in their own tab, in the right monitor, Scanned each question quickly, and voted on the Meta answer (most of my votes were downvotes), Repeat for the next one, and so on...   I didn't spend more than a few seconds on any question, as I'm fairly regular on the site and I've already read all of them while casually browsing the site. In fact, if my memory isn't failing me, I had voted (up/down) and/or commented, and/or voted to close on each of the 20 example questions. I might have spend a minute or two re-reading a couple, but I mostly scanned through them. In any case I think my voting pattern is quite normal, and the script should be somehow tweaked to take serial posts, posted by the same user in quick succession, into consideration, especially on Metas.   Since I had anticipated that the script would kick in, I could have tried to fool it by pausing a bit between votes or trying to look for other Meta posts to vote on, in between voting on the evaluation answers. However I'm a very active voter on Meta Workplace, there aren't many posts I haven't already voted on, and the few that I haven't is probably because I neither agree or disagree with (my opinion on them is simply "meh"). In any case I think my voting behaviour was natural, and although the serial voting script is awesome, this time it caught and reversed a perfectly legitimate behaviour.  Animuson, in , mentions that the script isn't really optimal on Area51 as well:      Yes, please implement this on Area 51 proposals too! Oftentimes a single user would suggest a plethora of "example" questions to their own proposal which are just terrible, yet all of everyone's votes get reversed and the question just sits there at 0. I've noticed several times that my votes have gotten reversed.    I haven't noticed it myself, but it certainly seems plausible, especially early in a proposal's life.  Mysticial found a related discussion, , but it's focused on voting patterns on main sites, where reputation is also a factor. I can understand jumping through hoops to satisfy the script on main sites where, unfortunately, there are a lot of people trying to get some cheap rep or "punish" others with their downvotes, but not on Metas, and especially not on these evaluation posts.   Voting fraud is a problem, and more often than not the script works wonderfully, but in my case it was extremely counterproductive. Critical evaluations are essential for a young Beta site, and their answers typically only get a handful of votes. I wonder how many of these votes have silently gone away...  Fix this please. How can I intercept XMLHttpRequests from a Greasemonkey script? Why is there a controversy on whether mass increases with speed? Why is the net speed of Stack Overflow so fast? This question is about the net speed.  I'm from China, and I find that opening pages on Stack Overflow is very fast, normally within a range of 1 to 4 seconds. This speed is very good for a website outside China; it's even faster than some native websites.  Not every website outside China has such good speed, so I am wondering why and how Stack Overflow manages to be so quick. What happens to a polymorphed character if he is shorn as a sheep? "strlen(s1) - strlen(s2)" is never less than zero When may adjectives precede determiners? (E.g. too difficult a task) The expression too difficult a task sounds a little pompous, but it doesn't sound ungrammatical. According to my folk-beliefs about English grammar, determiners precede adjectives. However, the expression too difficult a task seems to controvert that belief.  Additionally, the expression too difficult of a task seems grammatical too.    Under what conditions may determiners precede adjectives? Are there conditions under which too difficult of a task would be a more grammatical expression than too difficult a task would be?   (This question does not ask what the question “How big of a problem” vs. “how big a problem” asks. That question does not pertain to determiners.) What's the difference between align and align*? After some brief searching I can't find the difference between align and align*. Google summarily ignoring the * is making it harder I think.  Can you tell me the difference between these two?  Moreover, can you tell me where you generally go for this type of information? As a relatively new user I'm still building up my resources. Does the sign of scores or of loadings in PCA or FA have a meaning? May I reverse the sign? I performed principal component analysis (PCA) with R using two different functions (prcomp and princomp) and observed that the PCA scores differed in sign. How can it be?  Consider this:  set.seed(999) prcomp(data.frame(1:10,rnorm(10)))$x              PC1        PC2  [1,] -4.508620 -0.2567655  [2,] -3.373772 -1.1369417  [3,] -2.679669  1.0903445  [4,] -1.615837  0.7108631  [5,] -0.548879  0.3093389  [6,]  0.481756  0.1639112  [7,]  1.656178 -0.9952875  [8,]  2.560345 -0.2490548  [9,]  3.508442  0.1874520 [10,]  4.520055  0.1761397  set.seed(999) princomp(data.frame(1:10,rnorm(10)))$scores          Comp.1     Comp.2  [1,]  4.508620  0.2567655  [2,]  3.373772  1.1369417  [3,]  2.679669 -1.0903445  [4,]  1.615837 -0.7108631  [5,]  0.548879 -0.3093389  [6,] -0.481756 -0.1639112  [7,] -1.656178  0.9952875  [8,] -2.560345  0.2490548  [9,] -3.508442 -0.1874520 [10,] -4.520055 -0.1761397   Why do the signs (+/-) differ for the two analyses? If I was then using principal components PC1 and PC2 as predictors in a regression, i.e. lm(y ~ PC1 + PC2), this would completely change my understanding of the effect of the two variables on y depending on which method I used! How could I then say that PC1 has e.g. a positive effect on y and PC2 has e.g. a negative effect on y?    In addition: If the sign of PCA components is meaningless, is this true for factor analysis (FA) as well? Is it acceptable to flip (reverse) the sign of individual PCA/FA component scores (or of loadings, as a column of loading matrix)?