This morning same thing, and eventually started running normally. However, this time after about 5 mins use, the fan stopped altogether (first time it has stopped after it has managed to get up and running). The problem is intermittent, is this a problem with the fan motor or with the motherboard. The PSU is 700W and should be adequate for my hardware.
The CPU cooler/fan is a Arctic Cooling AC-FRZ-7P Freezer 7 Pro
The mobo is a Gigabyte GA-P35C-DS3R
OS XP Pro with sp2