Win 7 x64 Freezes on start up

[jodubs]

Hello,

I had been running Windows 7 Ultimate x64 for at least 6 months without any problems. The other day while just browsing around on my computer, Windows locked up - no BSOD, mouse doesn't move, keyboard doesn't respond. I did a hard reboot and now Windows continually freezes on start up. Sometimes it freezes on the 'Welcome' screen and other times it will freeze just seconds into loading the desktop.

I went into my BIOS and loaded my defaults. I then went into safemode (which works fine) and downloaded an updated BIOS which I flashed in DOS. This did not help. I backed up everything I needed onto an external hard drive and formatted my hard drive. After a clean install of Windows, everything seemed fine. After installing drivers and Windows updates, my computer randomly froze again and then the boot freezes began again. If I turn off all services, including Windows services, I am able to boot properly, which leads me to believe it may be a Windows service that is causing my system locks.

I have ran chkdisk and WD drive utility which have turned up no problems. I removed and reseated each stick of RAM and tested each one independently. I also ran stress tests on the CPU and memory with no problems. Temperature is not an issue. I checked and reseated all SATA cables. The only thing that I have not checked is that my power supply is giving a constant current.

The nature of how the freezes randomly began screams hardware, but the fresh installations of Windows and repeated boot problems scream software. I am running out of ideas. Any suggestions are greatly appreciated.

Thanks

EDIT: System specs

EVGA P55 SLI
Intel Core i5 750 w/ aftermarket heatsink
2x2GB G. Skill Rip Jaw DDR 1600
EVGA 8800 GTX
Razer Barracuda AC1 Soundcard
WD Caviar Black 750 GB HD

 

[richc46]

Run a full anti virus scan
Download and run the full malwarebytes scan. Make sure it is updated before the scan.

Once certain it is not malware, we can try an sfc scan, etc.
Since safe mode works, after the scan try a clean boot.
http://support.microsoft.com/kb/929135

 

[jodubs]

Run a full anti virus scan
Download and run the full malwarebytes scan. Make sure it is updated before the scan.

Once certain it is not malware, we can try an sfc scan, etc.
Since safe mode works, after the scan try a clean boot.
How to troubleshoot a problem by performing a clean boot in Windows Vista or in Windows 7

Is it possible to have malware on a clean install where the hard drive was fully formatted?

 

[richc46]

Probably not, but that is my first suggestion. Lets get that out of the way. Then you try my next, which should work. Maybe during that short time, while you were d/l the anti virus your caught something

 

[jodubs]

Thanks for your quick replies. Going to try your suggestions now.

 

[richc46]

I think the clean boot will work, but lets just get that bad stuff out of the way.
You could have caught something while you were d/l the antivirus. I d/l to a finger drive, so I do not have to be on line without protection, after a clean install.