Originally Posted by birdy123
I agree with you but the thing that is confusing me is that its boots to windows and happily sits at the logon screen and will change the screen to log me on a different user, but as soon as I log on it crashes. What could the GPU be doing during the logon phase that it has not done to display the logon screen? Quite strange. I have added more thermal paste, reseated the block and will reconnect and try again tonight. I've also asked some over on the nVidia forum as well. Hopefully I dont need to buy a new GTX.
A lot of things, honestly. Just like playing Crysis or Metro will break "stable" overclocks by stressing or accessing parts of the video card that were previously not so stressed or accessed, different parts of a video card could be accessed while loading Windows (including Aero).
You didn't have any electrostatic shocks with the card, did you? I can't think of anything else other than that or physical damage so long as you didn't bump something else out of place while installing your loop (either end of the PSU 6-pin connectors, RAM, etc.)
The good news is that, assuming you've got the stock screws and such lying around, you can RMA the thing since there's no visible damage.