I know this question has been tackled in a couple different threads but I've tried what I could from those and have not resolved the issue. I have just a basic understanding of this system so feel free to talk down to me or explain this like you would to a 5 year old.
Let's start from the beginning. My son has a computer built by an IT friend of mine (we moved so he can't help any more). It had Windows XP running on it and it just stopped working correctly. This same friend had built a laptop for me with Ubuntu which I liked so I thought I'd put a new OS on my sons computer and it may work better. I downloaded Ubuntu 12.10 onto a USB drive and loaded it onto his computer. I followed all the prompts, it installed, I restarted the computer, it gives me the option of which OS to pick. I pick Ubuntu and it seemingly loads. The desktop comes up with just the basic pinkish Ubuntu background but that is it. There are no icons. I can't right click anywhere to create a file. Left clicking the mouse does not create a square when moved. Alt + F2 doesn't do anything. I can open a terminal but any of the commands I have seen in previous threads do not correct any issues.
What else can I do, or what resources are available to fix this problem? I don't know if there are additional files on the USB drive that I need to access or what.
Also, one of the problems we were having with my sons computer is that windows would only load to a blank screen. It runs accordingly in safemode and my install of Ubuntu was through safemode of Windows XP.