Windows Restarting itself at log in screen.

I have been running dual boot OSX and windows labs in a University for a few years now so have plenty of experience with it, however today I am seeing something that I have never seen before.

I have iMac's running OSX Lion and Windows 7 64bit Enterprise, they are both joined to the same windows domain controller. Lion seems to work as Leopard and Snow Leopard did and I have no problems. However with Windows 7, after the iMac's are turned on and boot in to windows they sit at the log in screen, if no one uses the computer at all and it's just idle after around 30 minutes the iMac reboots.

Has anyone seen this happen or is there some sort of power setting I am missing in 7 that is causing this to happen? Would it happen if the time in Windows is out of sync with the domain controller by more than 15 minutes?

Thanks in advance for any help at all!

 

Just on the off chance anyone else ever comes across such a problem, the computers were blue screening, this was due to McAfee centrally managed anti virus being pushed down through group policy and not correctly installing.

 

I doubt anyone will read this but the actual problem was more to do with Windows trying to use the HFS+ drive.

Once I joined the domain, McAfee was trying to scan it, a script on the domain was trying to write to the D: drive which was the HFS+ drive and windows 7 was trying to use it for part of the page file, this was causing the imacs to blue screen.

Once I removed the drive letter from the HFS+ drive in disk management the blue screen has gone as nothing tries to write or scan the drive now, I had my lab of imacs on for 72 hours under a medium load in windows 7 and didn't experience any blue screens.

The blue screen error was: Page Error in Non Paged Area