Ok, so my PC has stopped booting 9 out of 10 times. When it does boot though it runs rock solid every time without issue. If I power completely off, chances are I won't be able to boot the PC, but if I hibernate, I can wake the PC back up and Windows will be rock solid. In a normal boot the PC would post, I could hear some type of fan or device spinning up once and then Windows (Vista) would boot. Now the PC successfully posts, but all I get is a blank screen save an underline cursor at the most upper left and I can hear the device repeatedly spinning up and down instead of the one time like normal.
Ok, so here's what's throwing me for a loop, the fact that it won't boot most of the time but when it does it is rock solid, and also the fact that I can boot from the recovery CD and run a memory diagnostic which will always find no issues, but at the end of the diagnostic it reboots the PC and most of the time it will sucessfully boot to windows (Vista).
My gut is telling me PSU but how would that explain the almost always successful booting after the memory test? On a side note the three diagnostics I can run, Mem, CPU and HDD always come back clean.
Any thoughts or ideas greatly appreciated as it's driving me batty.