I just inhereted a Dell PIII running Windows 2000. Every 2 or 3 hours (even if no apps are running) it starts slowing down to a halt. The mouse will take forever to move across the screen as if I'm using up too much memory. When I look at the task manager, the CPU usage is spiking at 98% usage but no apps are running. I reboot and everything is fine for a couple hours. I've run Norton AV w/ latest Defs and dont find a virus. Any suggestions??