KT7 and reboot at network login

[Pederv]

I have 2 systems built on the KT7-RAID with a 800MHz Thunderbird OC'd to 900 on each. Each board has a Modem Blaster 5601 and that's where the simularities end. Each board has a different video card, different nic card and one has a SCSI controler and the other has an SB Live. But both have the same problem, when the hardware is moved or the drivers installed, both systems will reboot at the network login prompt. The reboot may happen only once but sometimes 2 or 3 times. When the system comes up and makes it past the network login, it's stable. Any suggestions?