Cooler Mater GX 550W

Hi,

I built my new system over the weekend and ran it for a good few hours with now problems at all.

However over the last couple of days the Cooler Master 550w GX has developed a teething problem, it is nice and quiet during POST and at the Windsor 7 login screen but as soon as I log in the PSU fan ramps up to top speed and stays like it.

I have a Antec 300 with all 5 fans on high so I do not think its a cooling issue.

I spoke with Scan who suggested it may be the temp sensor so have sent me a new one, however I have just installed it and still have the same problem..

Any ideas?

Thanks, Will.