I don't know how to help you, but it sounds like you might have an assload of spyware and viruses. The same thing happened to my computer. It has 512 MB ram and a pentium somethingdecent. Turns out I had over 76 thousand spywares and over 100,000-170,000 viruses. (Can't remember which number it was). It was running pretty sluggish... Maybe you should get that checked out?

Oh yeah, whenever I would run Norton it would slow the thing down almost to a complete stop, and my virus protection had also expired.