I installed the driver using apt-get and restarted my computer, and now when I log in. I get stuck in a loop. The screen shows some funny colours and sends me back to the login screen. Is there any way I could do a system restore back to my old graphics settings? any help would be much appreciated :)
My Ubuntu is stuck in a login loop when trying to enter my desktop. When I login, the screen gets black and soon after that the login screen comes back.   I've read that the problem might be caused by an error depending on the graphics, here's my graphics card: ATI Radeon 7670M
Do I need a license to create pdf files? I hope this is the correct place where I could ask this question. My mother is an accountant with a degree in economics. She works as a freelancer and she needs some licenses for her job.  The biggest problem is adobe acrobat standard, which costs 400€, quite a lot. I want understand if she must buy it to create pdf files or she can use some free (even for commercial use) programs that she has because of her job (the chamber of commerce provide some advantages to accountants).  She is actually using PDFCreator, which as I can read is free for business usage (open source also!!):   Thanks for any suggestion Can a Paladin take levels of other classes? In 3.5 D&amp;D,  have severe restrictions on multiclassing:     Like a member of any other class, a paladin may be a multiclass character, but multiclass paladins face a special restriction. A paladin who gains a level in any class other than paladin may never again raise her paladin level, though she retains all her paladin abilities.   Because Pathfinder is based on 3.5 D&amp;D, do Pathfinder paladins face the same restriction? That is, if a Paladin multiclasses to say, a fighter, can she take another level of Paladin later on? Prove that , any primitive root $r$ of $p^n$ is also a primitive root of $p$ For an odd prime $p$, prove that any primitive root $r$ of $p^n$ is also a primitive root of  $p$   So I have assumed $r$ have order $k$ modulo $p$ , So $k|p-1$.Then if I am able to show that $p-1|k$ then I am done .But I haven't been able to show that.Can anybody help me this method?Any other type of prove is also welcomed. Using "that" and "this" interchangeably Learning and using English I'm always confused about what word to use for referring to things that have been described by me a few sentences earlier: "that" or "this".   Confusion comes from the fact that only the equivalent of "this" is always used in my native language for such referring. But I've noticed that in English for such referring "that" is used as often as "this" (or maybe even more often).  Some examples for illustrating (just tried to google something appropriate to convey my idea better):     We assess local... the demographics of the local population. What are the natural traffic drivers in the area. Things like cinemas and pubs and retail and office and all that type of things and we now put together a bit of a matrix and actually give a weighted score to each of the things we know help our business. That helps us decide in a more scientific fashion.   or:     The problem of Cervantes' origin became after that into a tough matter. Some experts believed that the Cervantes from Alcázar, in the times of the Lepanto Battle, was in the age of a child, more concerned about gathering nests and that type of things than about fighting as a soldier.   and for "this":     I believe lot of people who involved fishery industries in Mexico Gulf are suffering now but as for economic issues, U.S government and other countries will support them and give an utmost response to it. Important thing is that we learn from this mistake and make sure this type of things will never happen in the future and protect nature environment thus we have to take this technology to get energy from water very seriously. I really hope this technology will be available and used for everybody as soon as possible.   Is there a rule describing proper usage of these words in cases like this? (or should I have written "..in cases like that"?) How to add home directory path to be discovered by Unix which command? Area of a parallelogram, vertices $(-1,-1), (4,1), (5,3), (10,5)$. I need to find the area of a parallelogram with vertices $(-1,-1), (4,1), (5,3), (10,5)$.  If I denote $A=(-1,-1)$, $B=(4,1)$, $C=(5,3)$, $D=(10,5)$, then I see that $\overrightarrow{AB}=(5,2)=\overrightarrow{CD}$. Similarly $\overrightarrow{AC}=\overrightarrow{BD}$. So I see that these points indeed form a parallelogram.  It is assignment from linear algebra class. I wasn't sure if I had to like use a matrix or something. How do I make a bootable Ubuntu USB? How do I make an Bootable Ubuntu USB containing the the latest version of Ubuntu?  For completeness, how would I be able to do this on Ubuntu, Windows, OS X or another Linux distro? How do remove "Ignoring file in directory /etc/apt/sources.list.d/ as it has an invalid filename extension? Why is the Descriptor not getting called when defined as instance attribute? What is the square root of complex number i? Is there any way, shape, or form that ultraviolet light is recorded by a digital sensor?  Ideally, this question is related strictly to the sensor, without even a glass lens in between which could cut or block UV light.  But of course I don't take pictures with a bare sensor, I also have a lens, so I'd also like to know how much UV gets to the sensor to begin with. Error message says I can't flag... but yes I can When trying to upvote a comment made on a locked post (ordinary lock, not historical lock which remove the vote arrows and flag altoghether) we are greeted with such error message:        Or in words:     This comment is not eligible for voting or flagging   Being the curious type, I went straight away and tried to flag, fully expecting the same message... just to see the flag dialog open up just fine:        I was able to flag as well.  Can the error message please be changed to just "This comment is not eligible for voting"? Or of course, if it's not the intended behavior really disable the option to flag?  The original post on which I experimented is now deleted, but  you can play with. Drupal out of the box comes with a page (which is the default homepage) that is assigned to the node path.  How do I avoid users reach it, and redirect them to the actual homepage of the site? Second order partial of $f(x,y)=\frac{xy(x^2-y^2)}{x^2+y^2}$ Consider the function $f(x,y)=\dfrac{xy(x^2-y^2)}{x^2+y^2}$ for $(x,y) \neq (0,0)$, $f=0$ otherwise.  I have to compute $\dfrac{d^2f}{dydx}(0,0)$.  I know that I have to calculate $\frac{df}{dx}$ first. But that is ,  $\frac{df}{dx} = \frac{\partial f}{\partial y}\frac{dy}{dx}+\frac{\partial f}{\partial x}$. When I put it in wolframalpha, it gives me this calculation, and also just $\frac{\partial f}{\partial x}$ as an alternative form.   Why do I just ignore the y'? I don't know what y(x) is, as a function of x.  y and x are independent functions, no? How should we deal with duplicate answers? Show that Function Compositions Are Associative In the cases of black holes that form from supernova and collapse of a massive star, I understand that in most of these cases, the star loses significant amounts of mass from the explosion. Presumably, after this point as the remaining mass becomes more dense as it further collapses unto itself, it eventually becomes a black hole with gravitational force greater than that of its parent star. But, if gravity is based on mass, how can the black hole have greater gravitational force than the star from which it is formed? Can I paste plain text by default? I regularly copy and paste text between spreadsheets, emails, browser windows, etc. I can't think of a single time when I've wanted to keep the formatting from the source text.  I already know about the following workarounds:   Use “Edit” → “Paste Special” → “Unformatted text” Paste to Notepad and copy from there Install a program that takes over the clipboard   What I want is to tell Windows to just do this by default.  Is this possible? I have scripts calling other script files but I need to get the filepath of the file that is currently running within the process.   For example, let's say I have three files. Using :   script_1.py calls script_2.py.  In turn, script_2.py calls script_3.py.    How can I get the file name and path of script_3.py, from code within script_3.py, without having to pass that information as arguments from script_2.py?  (Executing os.getcwd() returns the original starting script's filepath not the current file's.) What are irreducibles in the ring $R$ of entire functions? Here's how far I have gone:  I first find the units in $R$. Let $f$ $ \in $ $R$ be a unit. Then $\exists$ $g$ $\in$ $R$ such that $fg=1$, i.e $f(z)g(z)=1$ $\forall$ $z$ $\in$ $\Bbb C$.  Then, $f(z)$ $=$ $\frac 1{g(z)}$ $\forall$ $z \in \Bbb C$. Hence $f(z),g(z) \neq 0$ $\forall$  $z \in \Bbb C$.  Now to find the irreducibles, let $f \in R$ be an irreducible. Hence whenever  $f(z)=g(z)h(z)$ for $g,h \in R$, then $g$ or $h$ is a unit.  Let $h$ be the unit and $\alpha$ be a zero of $f$. Then $f(\alpha)=g(\alpha)h(\alpha)=0$ $\Rightarrow$ $g(\alpha)=0$. Hence $z-\alpha$ is a factor of $g$. So $g(z)=(z-\alpha)^ng_1(z)$ for some $n \in \Bbb N$, where $g_1$ is unit. Since $f$ is irreducible, hence $n=1$.  I'm stuck here. What can be my next step?