HELP! Something wrong with my pc!

So last night I left my pc on running prime 95 and I let that run through the whole night then I got up in the morning and everything was still good, so I closed it down and went to school and when I come back home my pc booted fine but for some reason it's stuck on windows classic theme, so I went to enable aero theme and it's greyed out! So I try reinstalling my gpu driver and it keeps saying its failing the installment! So I go on the web and it won't work. Wtf is happening its like somebody has broken into my home and uninstalled every thing on my computer. I can't even instal windows 7 updates

Sorry if this is the wrong forum but I'm kinda assuming it has to do with graphics and displays or something. Can somebody plz help me I don't know what to do, I can't even install anything