After running reliably all not doing the virus scan and working from 6 am (Perth West Australian Time) it died at 8:00 am exactly. How does one tell if ones dial up ISP is pulling the plug on you? Would this cause the system to feeze? I also had a problem that on boot up Outlooks sound had gone but on third reboot they reappeared; weird.

All the freezes/crashes seem to happen when CPU usage is at max if that's relevant. The CPU fan and it an its heatsink are working and firmly attached.