I am running Windows 7 Build 7100 64 bit on an HP A6720F, Quad core AMD with 6 GB RAM. I did an upgrade from Vista SP1 and everything seemed fine. Now after 30 minutes or so, all 4 CPU's start running at 80-90%. Checking Task Manager processes only show about 3-4% usage, mainly from anti-virus and Task Manager itself. I manually shut down all services (Allowed) and no effect. A restart brings all back to normal. RAM isn't affected and stays about 1.4 GB used. Has anyone experienced this issue? I really don't want to do a clean install because I have lots of applications I use that would have to be manually re-installed...HELP!!!!!