I ran into this problem with a friends computer this evening. Tried many of the suggestions, and still don't know why or how this happens so I'm sure there are instances when any one, or combination, of the things you come across work but here's what worked for me.
Symptom:
Windows 7 laptop boots up to logo then no login screen, just sits there.
Here are the steps I went through (I've put asterisks next to the ones that were usefull, but wanted to be thorough):
Attempted to boot to safe mode....no luck
*Hit F8 at startup to get to the repair mode and ran a system restore to the oldest date available (approximately 3 weeks earlier).
*After system restore completed the problem was still there, however I could now boot into safe mode.
Uninstalled the video driver and restarted. Problem not resolved.
Reboot to safe mode, downloaded Malwarebytes and did a quick scan, found 33 items. Also ran microsofts fixit tool which removed to add ons that were on IE.
Restarted, still had the intital problem.
Booted back into safe mode, ran sfc /scannow - no problems showed up.
*While still in safe mode, added a second user (saw this in a forum so extra props to who posted it)
*Restarted the pc and now was able to reach the login screen and was able to login as the original user (both original and newly added users did show)
So for me the key was using repair mode to run system recovery allowing me into safe mode. Then adding a second user. Why this worked I have no idea but those three steps got me back into the machine and now I'm just cleaning up the crap, malware, resetting internet settings, removing shady toolbars and applying Windows Updates, etc. I'm going to then remove the user I added and hope everything is cool.
Thanks to those who have posted in this, and other forums, it was a combination of trial and error with the different suggestions that got things back to "normal". At least I'm able to log in now and clean it up without a having to do a fresh install.
Hope this helps, again, the credit goes to all the others that posted.....if anyone knows why adding a second user was the key I'd love to know!
-Byrnie