My system hangs for no reason. It hangs on a completely random basis. It hangs during the Boot Up sequence, in DOS, Windows Normal and SAFE MODE and even during Internet Sessions. I have checked for Viruses, replaced a few VMM32.VXD driver files,checked the memory, CPU, Hard Disk, Motherboard, Power Supply Unit and the Registry, but they all tested OK. Unfortunately, when I realised the problem System Restore was not working. I appreciate that the information given is not specific, but could anyone please help? I would appreciate any suggestions apart from those I've already mentioned.