suddenly windows...

[Axxion V]

out of nowhere windows stopped loading after post...

Windows 7 64-bit
phenom 9950 140w
biostar ta790gx am2+
2gb kingston (cheaper stuff) 2 x 1gb
kingwin 610w PSU
sapphire HD4870
VisionTek 450w Dedicated PSU for HD4870
2 x 80gb western digitital HDD raid 0
1 x cd/dvd
1 x card reader
1 x floppy
4 x 120mm fans

I had 4 x 1gb of ram when i installed windows 7. i ordered 2 x 2gb ocz 1066 off ebay so i pulled 2 x 1gb and gave to a friend leaving me with my 2 x 1gb. then pc was still booting fine with just the 2 gigs. one night i turned the pc off and the next morning i tried to turn it on and it would go through the whole post process but then hangs on the screen displayed just before the loading windows screen appears. i also hear the single beep (successful post beep) im guessing its my hard drive but i truly have no idea. how do i troubleshoot this?

p.s. i never received my ocz 2x2gb 1066 so i still have the 2x1gb kingston

 

[Lexluethar]

Run memtest+ or the memory test that comes with windows to see if this is a memory issue.

Can you boot into safemode?

 

[Axxion V]

i tried to boot into safe mode with no success. i noticed that pressing the f8 key did nothing at all. i could not even get into the menu that asks how you would like to try and boot. so i went into the bios and noticed some bios setting had been changed all by itself. primary boot device was set to usb flash and boot priority was also usb flash as 1st. so i fixed the problem but i just dont understand why bios settings would change by itself.