It's probably not the graphics card causing your problem. It's probably spyware/malware and need to clean out junk from your computer. A clean install will fix the problems, but it isn't necessary unless the junk in there is so bad you can't fix it.

I really don't think this is a hardware issue other than the graphics card. If you can, install this program and have it read what the name on that graphics card really is, then post what it says in here.
http://www.cybertechhelp.com/downloa...t-home-edition