I had the same problem. Reboots when switching accounts, but it was random. It might switch 8 times then it would reboot. I went to user accounts and disabled the rebooting in order to get the blue screen failure and error dump. I tried all the usual tricks - cleaned registry, used run sfc scannow, etc. etc. I finally called in a Tech and explained what was happening. Of course it would not fail when I switched accounts. - finally it did! There was a red square in the blue screen error message, so he said it was my video card. He searched for the updated drivers for my Radeon 7500 and installed them. It worked! So here is one solution that worked. Try using the device manager to update your drivers or the MS Update, but look for the options, not the essential ones. It just so happened that my old monitor worked without the updated driver but the new one did not. Good luck.