I have a laptop with Windows 8.1 and every time I restart the computer it's like Google Chrome reinstalls itself from scratch. My browsing history, download history, extensions, themes, etc... all disappear.  I have reinstalled Chrome more than 5 times attempting to solve this problem, with no effect. I avoided restarting Windows for several weeks to avoid the issue, but now I'm tired of this. I don't know what to do. I like Chrome and don't want to switch to another browser, but it seems I don't have a choice. Can anyone help?  Other details: I tried signing into a Google account using Chrome. I scanned the system with Malwarebytes and Avast more than 10 times. I formatted and reinstalled my operating system 3 times.  I do have malware in my system, but they are not going away. The one malware annoys me most is "bettersearch.tk".
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.
What does this black-font Israeli stamp on my Passport mean? I applied for B2 Tourist visa at Israel embassy in New Delhi last week. But my visa application got rejected and stamped a black stamp on my passport.   What does black stamp mean? After how much time should I reapply for tourist visa? Show $S = f^{-1}(f(S))$ for all subsets $S$ iff $f$ is injective Let $f: A \rightarrow B$ be a function. How can we show that for all subsets $S$ of $A$, $S \subseteq f^{-1}(f(S))$? I think this is a pretty simple problem but I'm new to this so I'm confused.  Also, how can we show that $S = f^{-1}(f(S))$ for all subsets $S$ iff $f$ is injective? Image of Stack Exchange button is blocked by Adblock Chrome and IE 11 are fine, I'm only able to reproduce this in Firefox. Using version 27.0.1 on Windows 7. Meta as well as all the other sites are affected.        I can still see the hover effect, but the image is gone. I see this in Firebug:        The image doesn't show up in the Network tab. I am able to see the image by visiting  which goes to   I've done Ctrl-F5, I've cleared the cache and I've tried Private Browsing. Possibly related to  ? I'm writing a bash script that needs to delete old files.  It's currently implemented using :  find $LOCATION -name $REQUIRED_FILES -type f -mtime +1 -delete   This will delete of the files older than 1 day.  However, what if I need a finer resolution that 1 day, say like 6 hours old? Is there a nice clean way to do it, like there is using find and -mtime? Why is OpenJDK 10 packaged as openjdk-11-*? Is the use of "one of the" correct in the following context? Easy to bypass "Are You paying Attention" test by viewing question in detail I think many of us already aware, still I wanted to let you know that First Post and Late Answers review posts are generated on specific time interval. When time comes for post generation I follow some tricks   Click and till a Post appears for review Then right-click and select Open in new tab 5-8 time. Then in every page follow the below steps   Open the Question of post appeared in review in New tab If Page/Question not exists then simply downvote since post was deleted because of -ve response. Else if page exists then   Check the review post's Net Reputation If reputation is -ve then simply downvote the post came in review Else one may select No Action needed.    This way if in any case a post comes for "Are you paying attention" can be handled easily.  I think if a post comes in review should not allow to view post. It's really hard to get started on Stack Overflow I have been on Stack Overflow for some time.  It is an AMAZING resource and don't know if I would've got through the past 18 months without it.  I love it!  Problem is that I have "1" reputation.  All of my questions have already been asked and answered.  My "new user restrictions" mean: - I can't vote up answers that were helpful. - I can't comment on answers.  I sometimes have a question to ask one of the users that answered someone else's question but I can't.  This is hard!  How do I get a break?  Do I have to troll for a couple of days/weeks/months to answer enough questions in the hope someone votes some of them up just so I can do some basic functions?  Perhaps the number of site visits and length of membership could count for something? Passive aggressive people will sometimes veil insulting, critical, derogatory or generally aggressive comments with humor. The patina of humor makes the comment seem like a joke, not to be taken seriously, all in good fun, and it safeguards the aggressive person. If someone gets offended, they are being too serious, can't take a joke, and so they cannot voice their upset without seeming to be the one escalating the situation, when in fact it was the aggressor who did that.   This behavior seems to lie on a spectrum. On one side are comments which are simultaneously aggressive and genuinely funny (though of course both, especially the latter, are fairly subjective). On the other side would be lame attempts at the behavior, something like "you are fat!... just joking!" in which nothing in the tone or delivery signals a register of humor. In the middle of the spectrum, I imagine, are aggressive statements genuinely delivered as jokes. Their register signals that they are jokes, but they are aggressive rather than funny. They are aggressive comments masquerading as jokes.      A friend once called this "joking on the square", but I have never heard or seen this phrase. This type of comment is both pervasive and psychologically subtle and in my experience there is often an exact word describing such things. If not a word, is there an astute phrase which cuts to the heart of this? What are the prerequisites to studying general relativity? This question recently appeared :     Slashdot posts a fair number of physics stories. Many of us, myself included, don't have the background to understand them. So I'd like to ask the Slashdot math/physics community to construct a curriculum that gets me, an average college grad with two semesters of chemistry, one of calculus, and maybe 2-3 applied statistics courses, all the way to understanding the mathematics of general relativity. What would I need to learn, in what order, and what texts should I use? Before I get killed here, I know this isn't a weekend project, but it seems like it could be fun to do in my spare time for the next ... decade.   It seems like something that would be a good addition to this site: I think it's specific enough to be answerable but still generally useful. The textbook aspect is covered pretty well by , but beyond that: What college-level subjects in physics and math are prerequisites to studying general relativity in mathematical detail? What registers to save in the ARM C calling convention? It's been a while since I last coded arm assembler and I'm a little rusty on the details. If I call a C function from arm,  I only have to worry about saving r0-r3 and lr, right?  If the C function uses any other registers, is it responsible for saving those on the stack and restoring them? In other words, the compiler would generate code to do this for C functions.   For example if I use r10 in an assembler function, I don't have to push its value on the stack, or to memory, and pop/restore it after a C call, do I?  This is for arm-eabi-gcc 4.3.0. formal proof from calulus Given $f:R \to R$, $f$ is differentiable on $R$ and $\lim_{x \to \infty}(f(x)-f(-x))=0$. I need to show that there is $x_0 \in R$ such that $f'(x_0)=0$  I am trying to prove it by contradiction .... so i assume there is no $x_0 \in R$ such that  $f'(x_0)=0$ this means this function is strictly monotonic because the derivative "respects" the mean value theorem so it cannot be negative and positive without passing a zero value ....  (from what i understand the derivative function of a continuous/differentiable functions isn't necessarily continuous but it still respect the mean value theorem i think it's called darboux's theorem )  now from $\lim_{x \to \infty}(f(x)-f(-x))=0$ ,we get $\lim_{x \to \infty}f(x)=\lim_{x \to \infty}f(-x)$  now the last step is the contradiction its very intuitive and even maybe obvious that we can't get $\lim_{x \to \infty}f(x)=\lim_{x \to \infty}f(-x)$ for strictly monotonic function but i cant think of a formal way to prove it . I recently moved from having a main site like www.example.com with a subdomain associated site yyy.example.com, to moving everything off the subdomain to a subdirectory like www.example.com/yyy/, with the same hierarchy underneath the subdirectory, and now yyy.example.com is just a redirect page to the subdirectory, so yyy.example.com/abc/page-x is redirected to www.example.com/yyy/abc/page-x and so on.  The effect has been that the traffic increased by several times (the total page views are more than ten times at the present rate) what it was to the yyy subdomain. Previously almost all of the traffic to the yyy subdomain was from the www site. This is from monitoring the old yyy site for a year or more.  I'm curious to know if there's any research or results which would indicate whether this is universal (subdirectories beat subdomains) or "just me". Long, blurry reflections in wet road Assume $f$ and $g$ are differentiable at $x$. Prove that $(fg)^{(n)} = \sum_{k=0}^n \binom{n}{k}f^{(k)}(x)g^{(n-k)}(x)$   I am assuming here $fg = f(x) g(x)$. Then we can prove this via induction. If $n = 0$ we have $1 = 1$ which is true. Now assume it is true for some $m$ we need to show it is possible for $m+1$. We have $(fg)^m = \sum_{k=0}^m f^{(k)}(x)g^{m-k}(x)$. How do we show that? Combine or rebase an arbitrarily large number of commits One of the joys of high-school mathematics is summing a complicated series to get a “closed-form” expression. And of course many of us have tried summing the harmonic series $H_n =\sum \limits_{k \leq n} \frac{1}{k}$, and failed. But should we necessarily fail?      More precisely, is it known that $H_n$ cannot be written in terms of the elementary functions, say, the rational functions, $\exp(x)$ and $\ln x$? If so, how is such a theorem proved?    Note. When I started writing the question, I was going to ask if it is known that the harmonic function cannot be represented simply as a rational function? But this is easy to see, since $H_n$ grows like $\ln n+O(1)$, whereas no rational function grows logarithmically.  Added note: This  asks a similar question for “elementary integration”. I guess I am asking if there is an analogous theory of “elementary summation”. Creation and annihilation operators in the hydrogen atom What defines the maximum size for a command single argument? How to use Fermat's little theorem to find $50^{50}\pmod{13}$?