Windows 7: Urgent! Black Login Screen

While I test Windows 8 Developer Preview, there was a disk checking and it was checking my Windows 7's HDD (I install Windows 7 and Windows 8 Dev. Prev. in different HDD). And when I configure back my BIOS priority to Windows 7's HDD, it was failed to start.

Then I followed the startup repair and it says that my HDD has errors. I wait around one hour and when i restart, I got black login screen.

I can't use "sfc /scannow" because it says that I have repairment waiting and I have to restart, but when I restart, there's nothing and I got my black logon screen.
I can't use system restore because it says that I don't have any restore point.
I don't want to lose any of my program. So, Clean install is the worst case.
I've waited the login screen to load around half hour and it shows nothing.
I can't use Safe Mode because it stucks while loading drivers.
I've tried Windows Memory Diag. and found nothing.

What else I can try?
I don't have Windows 7 branding, shutdown button, and accessibility button (like others do) on the bottom of my login screen. I just have my working pointer on the screen.

No other choice.
I'll reformat (clean install). It's the best for now.