Running into a strange problem and not sure how to solve it.

Installed a water cooling system a few weeks ago. When I brought the
system back up, the onboard lan no longer worked (a Realtek 8139
chipset). It disappeared from the device manager altogether and
appeared to be gone from the system.

I assumed something got klutzed and put in a new NIC. When I installed
the new NIC, the onboard lan appeared in the device manager once again
and was functional. After I restarted the computer, both the new NIC
and the onboard lan disappeared from the device manager again and
neither one was functional.

Removed the new NIC, the onboard lan came back until I restarted, then
vanished again. I installed the new NIC a second time, which did
nothing. I have been without network connectivity on that box ever
since.

I reinstalled Windows XP to try to correct the problem, and it seemed
to fail to find either the new NIC or the onboard lan. Then I installed
another new NIC, which brought up the first NIC and the onboard lan.
When I restarted, all of them went away.

I do not believe this is a hardware problem. Booting under knoppix
brings up the onboard LAN with the NICs and each one is functional. The
water cooling kit draws power from 3 sources: the heatsink plugs into
the cpu fan 4 pin connector on the motherboard, the radiator plugs into
the standard power supply, and the water pump plugs into a second 4 pin
connector on the motherboard. It's a thermaltake big water kit and I
have used it on other XP systems (but different motherboards) without
incident.

So, I am thinking this is a Win XP problem but I am not finding any
solutions in the knowledge base. Any help would be appreciated.

M