I have a couple of machines on the network which, periodically, lock up completely, requiring a reboot. On rebooting, the machines fail to pick up their IP addresses (Static). If shut down again and restarted they finally pick up the IP address and connect to the network for a few hours before crashing again.

The machines are Compaq Deskpro EN6733+ with Intel(R)Pro/100 Management Adapters (NICs)