Stuck at "Loading Operating System..." with Gigabyte P55 motherboard.

[JaYp146]

Okay, I'll try and describe this as simply as possible.

I've had the 7100 build of Windows 7 x64 installed for a while now (since summer) on my main rig. I recently switched motherboard and CPU to something newer (P35 to P55 chipsets), which went smoothly. Windows 7 booted just fine. I fixed the registry to accept AHCI mode, switched my main OS drive from IDE to ACHI, and everything worked beautifully.

HOWEVER, upon switching chipsets, you're required to reactive Windows 7. I did so, restarted the computer, and ran into the issue described above - I get the "Loading Operating System ..." message just after the POST, and it's stuck. There's a cursor blinking below it, but it doesn't go anywhere. I can Ctrl-Alt-Del out of it with no problem.

I've messed with the BIOS thoroughly - tried IDE and AHCI mode, tried disabling USB 3.0 and SATA 6.0, I've run MEMTEST (and the RAM passed), tried pretty much everything.

Board is a GIGABYTE P55A-UD3, F4 BIOS, and the HDD is a Samsung F1 1TB.

I didn't set a system restore point (d'oh), so ...

 

[AlucardX]

only thing i could say is do a fresh install, setting up AHCI properly ahead of time along with the appropriate drivers required.

if you need backups from your C: partition.. try an external drive and boot of a linux live cd or put the drive into another machine as a slave.