I don't know if this will work but This has happened to me in the past.
What I did was:
1. Clear History
2. Run prefetch -> Delete all files inside folder
3. Run %temp% -> Delete all files inside folder
4. Run CC cleaner (if you have , if you don't get this free app
HERE)
AFter those steps, It will hopefully solve your problem with logging in the main site...
Good Luck dude