Do you have any visible glitches in the openning screens. I had a can't boot into windows except in safe mode issue when my old Nvidia flamed out. If there are any graphics issues windows will fail in self protection mode and auto-reboot is the default setting when that happens, (found this by doing a manually stepped normal boot from the safe mode menu) If you do change mobo's, I recommend ASUS. Never had a bad one yet and I have had a few.

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