Your computer is obviously not feeling too well at all.
There's probably not going to be any fixing this without a full format and reinstall.
Maybe check your memory, CPU, and hard drive with the tools on the "Ultimate Boot CD" first, to make sure it's not a hardware issue. http://www.ultimatebootcd.com/
Have anti-virus installed? AVG Free Edition works good if you don't. http://free.grisoft.com/doc/5390/lng/us/tpl/v5