Windows 7: BSOD after upgrading to Windows 7 Ultimate

Hello!

About a week ago I updated my computer to Windows 7 Ultimate. Since then, 90% of the time, when I boot up the computer a black screen appears on my screen and no desktop shows up. I can't do anything like get to to a task manager but the computer works fine in safe mode. Strangely, if I leave the computer for a couple of hours the black screen disappears and everything works perfectly.

Any help with fixing this problem would be hugely appreciated. Thank you

When does the black screen appear? After windows is starting animation, or after logon?
Has it a blinking cursor? (most of time top-left of screen)

It appears after the Windows flag comes up on screen so the logon screen doesn't come up. However, I can log on to my user if I press enter on the log on screen but I just can't see anything because of the black screen. And no, there is no blinking cursor.

after windows starting flag the logon screen appear after a short black screen. The short black is because switching resolution I think. At least so it should work. If pressing enter now, it logs in under first name listed in logon menu and desktop icons appear.

How do you know it logs on succesfully??? You only see black screen so how do you know?

I can hear the log on noise it makes so I can tell it's logged on! The black screen is just in the way and then, after two hours, everything works. I have tried to reinstall Service Pack 1 and done a bunch of other recommended stuff but nothing has worked.

If course the cool logon sound was appearing in your ears ;-) didn't think of that

Is this a laptop or deskop pc?

Haha, of course its a desktop pc.

Uninstall your Display Adapter drivers while in Safe Mode, then reboot, and see if that helps - then download and install a fresh set.

I have the same problem....Think it's just screen refresh rate....