Virus?

[mgs29035]

Over the past week, my computer's performance has degraded substantially. It runs slower, the CPU usage goes to 100% and stays there. Some applications don't work sometimes, I have to restart frequently to get them to work.

I've run my virus scan and adware software, it hasn't found anything. I'm almost sure I'm infected with something. I went to www.anti-virus.com and ran the free software there, still no good.

Any help would be greatly apprecitated.