After installation I am getting like this:  E: Failed to fetch http://archive.canonical.com/pool/partner/s/skype/skype_4.2.0.11-0ubuntu0.12.04.2_amd64.deb  404  Not Found [IP: 91.189.91.15 80]    E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?
I want to install Skype, but I can't locate it in Software Center or by using Synaptic Package Manager. Can anyone help me?
@future method: Unsupported parameter type Prove that a graph with the same number of edges and vertices contains one cycle $N_1,N_2,N_3 \unlhd G, N_i\cap N_j =\{e\}, G = N_iN_j$. Want to show that $G$ is abelian, $N_i$ are isomorphic. The following is a problem from the Berkeley Problems book.      Let $G$ be a group with three normal subgroups $N_1$ , $N_2$, and   $N_3$. Suppose $N_i \cap N_j = \{ e\}$ and $N_iN_j  = G$ for all   $(i,j )$ with $i \ne j$ . Show that $G$ is abelian and $N_i$, is   isomorphic to $N_j$ for all $i, j$ .   Attempt:   I have not got very far. The only thing that comes to my mind is that as $|HK|=\frac{|H||K|}{|H \cap K|}$, $|N_1|=|N_2|=|N_3|=m$, and order of $|G|=m^2$. I have made other futile attempts of trying to show m prime, finding an isomorphism between the $N's$. I think the fact that the equation $N_i N_j=G$, could be seen as, left coset of $N_j$ with the multiplying elements restricted to only $N_i$ could provide me an answer, but I haven't got anywhere with this.   Thanks in advance. How do you integrate $e^{x^2}$? I know that $\int{\frac{1}{x}}dx$ is simply $\ln{(x)}+c$ (-which is clearly unrelated to the problem but I just thought I would share anyway) but I am not sure how to approach $e^{x{^2}}$. Perhaps a substitution? SSL certificate for a public IP address? I just tried buying a Comodo Positive SSL but it was rejected due to not supporting a public IP address, but instead they only support a domain name.  Does anyone know any SSL certificate provider that supports public IP address instead of a domain name?  My company has a dedicated server hosted with a web hosting company, which is used for running a bugtracker for multiple projects (for multiple clients). Since it's only used for a bugtracker, we don't need a domain name (our clients access it by typing the public IP in their browser). What are a few examples of noncyclic finite groups? I just want to make sure that every group $\mathbb{Z}_n$ for any $n$ is cyclic. Further, every group of prime order is cyclic because it is isomorphic to $\mathbb{Z}_p$. I think I have a handle on that, but what other finite groups are there that aren't cyclic? In particular, I'm looking for examples that aren't direct products of groups, just simply groups like $\mathbb{Z}_n$, not $\mathbb{Z}_a \times \mathbb{Z}_b$, etc. Why does Ubuntu fail to run .exe files? / How do I run .exe? Is there a replacement for unistd.h for Windows (Visual C)? I'm porting a relatively simple console program written for Unix to the Windows platform (). All the source files include "unistd.h", which doesn't exist.  Removing it, I get complaints about misssing prototypes for 'srandom', 'random', and 'getopt'. I know I can replace the random functions, and I'm pretty sure I can find/hack-up a getopt implementation.    But I'm sure others have run into the same challenge.  My question is: is there a port of "unistd.h" to Windows? At least one containg those functions which do have a native Windows implementation - I don't need pipes or forking.  EDIT:  I know I can create my very own "unistd.h" which contains replacements for the things I need - especially in this case, since it is a limited set. But since it seems like a common problem, I was wondering if someone had done the work already for a bigger subset of the functionality.  Switching to a different compiler or environment isn't possible at work - I'm stuck with Visual Studio. Update Migration Path List for Non-Moderators Does installing and using Wine open up your Linux platform to Windows viruses? Just wondering if installing Wine might open up a fairly solid Linux desktop to the world of Windows viruses.  Any confirmed reports about that?  Would you then install a Windows antivirus product under Wine? How to run a fresh version of AIX in a Virtual Machine with a Linux host? Ampere's circuital law for finite current carrying wire When I was studying about . Then there comes a question in my mind that "whether this law is applicable for finite current carrying wire or not" How do I pass a string into subprocess.Popen (using the stdin argument)? What is the main difference between an inner class and a static nested class in Java? Does design / implementation play a role in choosing one of these? Compute $ \int_{0}^{ \infty }\frac{\ln xdx}{x^{2}+ax+b}$ minimal polynomial of powers of a matrix I am wondering, given the minimal polynomial of $A$, what can we say about the minimal polynomial of $A^n$?  I know that if we were looking at the roots of the characteristic polynomial ie eigenvalues then the roots of the characteristic polynomial of $A^n$ would be $nth$ powers of the eigenvalues so again these are roots of the minimal polynomial also. I have a MicroSD card in a USB adapter (which plugs into a USB port on my machine, and acts like a USB flash drive). I was using Unetbootin to make this a bootable USB flash drive with Kubuntu. But I needed to cancel while it was working. So I killed the Unetbootin process from the console.  Since then, I can't format the MicroSD or delete the folder that Kubuntu made. I have also tried mkdosfs, with no success. I can't mount the drive anymore either? What can I do to make this drive usable again?  Trying to create a new partition table in GParted, as described in Eliah Kagan's answer, does not work. It fails with the error message "imposible crear tabla de particiones" ("unable to create a partition table"). Can a package overwrite the original commands in Latex? An example:  Without the amsmath package:   The equation environment numbers the equation automatically. The align environment cannot be executed.   With the amsmath package:   align and equation work seamlessly in numbering equations: I can use equation to write my first two equations, and align to write my third equation, and Latex will still number them correctly.   My questions are:   Is the code for the command equation after loading the amsmath package still the same as it was before loading the package? Moreover, if this is the case, then, in general, can loading different packages cause conflicts? And how do we avoid it? How do I convert a light circuit with a single pole switch to use two 3-way switches? I have a box in the hall which includes a 3-way switch (with another switch at the other end of the hall), a single pole switch to the garage lights and a single pole switch to the exterior lights on the garage.  The single pole switch to the garage is wired with a 3 wire plus ground. The white and black wires feed the garage lights from the switch and the red wire feeds the garage ceiling outlets and is hot all the time.  In the garage I would like to add a 3-way switch for the garage lights and another 3-way switch for the exterior garage lights.  In other words I would like to be able to turn on both of those light locations from both the inside hall and the garage as well. I know that I will of course have to replace the existing single pole switches in the hall with 3-way switches and add a junction box in the garage with 2 3-way switches in it.  The thing that I don't know is what wiring connections I need to make.  Can you help? UK Standard Visitor visa application to sit for PLAB 1 without savings or job