Gray screen instead of login screen

I was hoping you could help with my MacBook Pro issues. First, my left fan was grinding so of course i blew out the fan (they were dusty). The laptop was also getting hot. After login I would also be presented with a white screen and no login screen would show.

I did every troubleshooting technique possible from:

1. repairing permissions - all fixed

2. resetting PRAM - was advised to release after 7 chimes

3. ran Techtool Pro 6 - no problems, not even video (card, memory... nothing)

4. ran Onyx (kinda like CCleaner). I cleaned EVERYTHING

5. took to Apple Store and they ran diagnostics and everything checked out. The fans even checked out

6. I was advised that my Hard drive was failing, but the SMART passed

7. As a last resort, I backed up, erased and reinstalled Snow Leopard thinking it may just be a something I installed (driver or something) causing conflicts. I'm still getting the white screen.

This is the funny thing, I safe boot the laptop and I get the login screen and everything is hunky dory. This happens every time I safe boot (no white screen)

I have done extensive research and tried everything presented to me to no avail.

Clean out your Windows PC computer

I was asked not too long ago to clean out an increasingly slow Windows computer.  CCleaner (formerly Crap Cleaner), developed by Piriform is a utility program used to clean potentially unwanted files and invalid Windows Registry entries from a computer.  A beta version for the Mac OS X has been released, but if you want a free, fully developed software package for the Mac, give Onyx a try