Yesterday i install gdm and set it default display manager then l notice ubuntu is running but there is several lines appear on desktop when i want to shutdown system after i powered off system and start Grub Menu appear and normal boot system but nothing is appear and black screen is regularly appear even after several restart.
I am trying to boot Ubuntu on my computer.  When I boot Ubuntu, it boots to a black screen.  How can I fix this? Table of Contents:
It's possible to offer and award bounties of reputation on questions.   What is a bounty? How can I find questions that have a bounty attached? How do I start a bounty? When can I start a bounty? Why is the system requiring me to choose a bounty amount that's higher than the minimum? Can I use Markdown formatting in the bounty remarks? Can I edit the remark? How long is the bounty period? How do I award a bounty? Can I award a bounty to my own answer? Can I award a bounty to an old answer? If I offer a bounty on someone else's question, can I award the bounty to their answer? After awarding the bounty, can I remove it or move it to another answer at a later time? What happens if there's no answer after the bounty period? What happens if I feel my question is still unanswered? What is automatic awarding? Are bounty awards exempt from the 200 points/day reputation limit? How does Community Wiki mode affect bounties? How does user deletion or post dissociation affect bounties? Can I award a bounty to an answer from a deleted user or one where the author was dissociated? Can I offer a second bounty after the first one has expired? Can I raise my bounty? What happens if a bounty question is closed or deleted? Why can't I vote to close or migrate a bounty question? What happens if I delete my account while I have an active bounty? Do I keep an awarded bounty when I delete my answer? What happens if a question where I awarded a bounty later gets deleted or migrated? Can I cancel my bounty? Can I affect / divide / share part of my bounty to two (or more) users? How many outstanding bounties can a single user have?      See also:  in the Help Center How do you end with a single quote followed by a double quote? I have a paragraph as follows:  ``This is a quote. `Here is a quote within a quote.'''   But the formatting works out to be a double quote (") followed by a single quote (') instead of the other way around. How can I solve this problem? How to resolve ambiguous column names when retrieving results? Is it possible to build a .dmg file (for distributing apps) from a non-Mac platform? And if yes, how? Is there a term for this word play where a song intentionally avoids completing a rhyme? Take this for example:  In this , at 1:04 to 1:10, the person goes on rapping with a rhyming word at the end of each line, but he pauses before the end of the last word and, being humans, we predict the next word (due to the hint from the rhyme) that he is going to say but he avoids it intentionally. Is there a word or phrase for this word play?     ...and the beat still knocks when I sort my socks   I'm five foot eleven of sex   from the tip of my head to my gorgeous...   knees    Not the best example I could find but I think it sums up my point quite well. If the edges of the complete graph $K_{17}$ (on 17 vertices with no three collinear) are each colored one of three colours can it be proven to have two or more monochromatic triangles? In the digital age of photography, we can see a range of digital camera sensors sizes in use, from 1/3.2" in small phones, up to Medium format sensors that are 53.4 x 40.0mm in size or more!  Why has no company endevoured to produce a sensor that can be considered to be large format (50mm X 80mm or larger)? Do such camera sensors exist in non-consumer products? the least possible value for :$ \lfloor \frac{a+b}{c}\rfloor +\lfloor \frac{b+c}{a} \rfloor+\lfloor \frac{c+a}{b} \rfloor $ If we know that for every $a,b,c&gt;0$ ,how we can find  the least possible value for :  $$ \lfloor \frac{a+b}{c}\rfloor +\lfloor \frac{b+c}{a} \rfloor+\lfloor \frac{c+a}{b} \rfloor $$ Cross product term in linear regression why is it zero I'm trying to see why this is the case. I have taken  the LHS and added $X\hat{\beta}$ and subtracted $X\hat{\beta}$.  From this I can get both terms on the right but I end up with a cross product term  $2(y-X\hat{\beta})^T(X\hat{\beta} - X\beta)$  that I can't prove equals to zero. I think there is some trick I'm missing, anybody remember it? Can decimal numbers be considered "even" or "odd"? NoSuchMethodError error for getActionBar() (API-8) Consider the group $\mathbb{Q}$ under addition of rational numbers. If $H$ is a subgroup of $\mathbb{Q}$ with finite index, then $H = \mathbb{Q}$.  I just saw this on our exam earlier and was stumped on how to show this. Any ideas? Traces of all positive powers of a matrix are zero implies it is nilpotent Let $A$ be an $n\times n$ complex nilpotent matrix. Then we know that because all eigenvalues of $A$ must be $0$, it follows that $\text{tr}(A^n)=0$ for all positive integers $n$.  What I would like to show is the converse, that is,      if $\text{tr}(A^n)=0$ for all positive integers $n$, then $A$ is nilpotent.   I tried to show that $0$ must be an eigenvalue of $A$, then try to show that all other eigenvalues must be equal to 0. However, I am stuck at the point where I need to show that $\det(A)=0$.  May I know of the approach to show that $A$ is nilpotent? When electric dipole placed in non uniform electric field, what is the approach to calculate torque acting on it? Can it be zero? How do you do Impersonation in .NET? Is there a simple out of the box way to impersonate a user in .NET?  So far I've been using  for all my impersonation requirements.  Is there a better way to do it by using .NET Framework?  I have a user credential set, (username, password, domain name) which represents the identity I need to impersonate. Efficiently select beginning and end of multiple contiguous ranges in Postgresql query I've got about a billion rows of data in a table with a name and an integer in the range 1-288.  For a given name, every int is unique, and not every possible integer in the range is present--so there are gaps.  This query generates an example case:  --what I have: SELECT * FROM ( VALUES ('foo', 2),               ('foo', 3),               ('foo', 4),               ('foo', 10),               ('foo', 11),               ('foo', 13),               ('bar', 1),               ('bar', 2),               ('bar', 3)      ) AS baz ("name", "int")   I'd like to generate a lookup table with a row for each name and sequence of contiguous integers.  Each such row would contain:  name   --  the value of the name column start  --  the first integer in the contiguous sequence end    --  the final value in the contiguous sequence span   --  end - start + 1  This query generates example output for the above example:  --what I need: SELECT *  FROM ( VALUES ('foo', 2, 4, 3),               ('foo', 10, 11, 2),               ('foo', 13, 13, 1),               ('bar', 1, 3, 3)      ) AS contiguous_ranges ("name", "start", "end", span)   Because I have so many rows, more efficient is better.  That said, I only have to run this query once, so it isn't an absolute requirement.  Thanks in advance!  Edit:  I should add that PL/pgSQL solutions are welcome (please explain any Fancy Tricks--I'm still new to PL/pgSQL). LaTeXiT is cropping the pdf I am using LaTeXiT (pierre chachatelier, www.chachatelier.fr) - latex equation editor for Powerpoint for mac.  It's producing pdf that appear to be "cropped" on top (see attached) - I've tried already with changing the "margins" option (Preferences>General) but unsuccessfully - don't think that's the problem.   Any hint?   Thanks What is the difference between a URI, a URL and a URN? People talk about URLs, URIs, and URNs as if they're different things, but they look the same to the naked eye.  What are the distinguishable differences between them? This is what I would like to do:  morekeywords={SENÃO, ENTÃO, FAÇA, ATÉ, ENQUANTO, PARA, SE, DECLARA, DECLARE, E, OU, FIM_ENQUANTO, FIM_PARA}   I'm defining a new language, and I would like to use natural language words as keywords.  The problem is with keywords: SENÃO, ENTÃO, FAÇA, ATÉ.  I have solved the first problem, in showing special chars with:   The alsoletter here, doesn't work for me, I got an error when using it: alsoletter={Ç,É,Ã}.  test.tex  \documentclass{article}  \usepackage[brazilian]{babel} \usepackage[T1]{fontenc}  \usepackage[utf8]{inputenc} \usepackage{listingsutf8}  \usepackage{listings}  \lstset{%         inputencoding=utf8,         extendedchars=true,         literate=%         {é}{{\'{e}}}1         {è}{{\`{e}}}1         {ê}{{\^{e}}}1         {ë}{{\¨{e}}}1         {É}{{\'{E}}}1         {Ê}{{\^{E}}}1         {û}{{\^{u}}}1         {ù}{{\`{u}}}1         {â}{{\^{a}}}1         {à}{{\`{a}}}1         {á}{{\'{a}}}1         {ã}{{\~{a}}}1         {Á}{{\'{A}}}1         {Â}{{\^{A}}}1         {Ã}{{\~{A}}}1         {ç}{{\c{c}}}1         {Ç}{{\c{C}}}1         {õ}{{\~{o}}}1         {ó}{{\'{o}}}1         {ô}{{\^{o}}}1         {Õ}{{\~{O}}}1         {Ó}{{\'{O}}}1         {Ô}{{\^{O}}}1         {î}{{\^{i}}}1         {Î}{{\^{I}}}1         {í}{{\'{i}}}1         {Í}{{\~{Í}}}1 }  \lstdefinelanguage{pseudo} { extendedchars=true, alsoletter={_}, morekeywords={ENQUANTO,PARA,SE,SEN\~{A}O,ENTÃO,ATÉ,FA\c{C}A,DECLARA,DECLARE,E,OU,FIM_ENQUANTO,FIM_PARA,FAÇA}, ndkeywords={NUMERO,TEXTO,LEIA,ESCREVA}, sensitive=true, morecomment=[l]{//}, morecomment=[s]{/*}{*/}, morestring=[b]" }  \begin{document} \lstinputlisting[language=pseudo]{foo.pseudo} \end{document}   foo.pseudo  ENQUANTO nota != -1 FAÇA // Comment example  LEIA nota  SE nota &gt;= 7 ENTÃO    ESCREVA "Aprovado"  SENÃO    ESCREVA "Reprovado"    TEST "Algo mais" /* mais  comentário */  FIM_ENQUANTO    I have seen: $\mathbb{Q}(\sqrt{p},\sqrt[3]{q})= \mathbb{Q}(\sqrt{p}\cdot \sqrt[3]{q})$ ??