do you have an Uninterruptible Power Supply?
There is more about using XP's UPS service here; http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/pwrmn_ups_overview.mspx?mfr=true
I have a Dell OU7670 and I gots a UPS prob. I have the UPS service on, I go 2 power options and it show connection failed or not turned on. Both fans are working, I have left hand side of putor open in case of temp probs(that's no the prob). XP home edition, so wasup w/that UPS.