|At this point I'd suggest you consider a clean install from the OEM disk or the recovery partition. I kind of doubt it is a hardware issue but could be. You could start off with the windows memory diagnostics that vista should have. See help and support for that.|
If you reload it, the first thing would be to get a good security suite. Make a standard user for you to use at all times and only use admin account to do special tasks. Then apply the updates and get your programs back. Put only the programs on that you know are good ones. Some downloaded ones are just malware.
1/3 of highway deaths are caused by drunks. The rest are by people who can't drive any better than a drunk.