Oh God I hope someone is able to help me!
I just upgraded from WP 2.9.2 to 3.0.4. I had no problems with the installation. I deactivated all my plugins before the upgrade but when I tried to reactivate them once the upgrade was complete I got a "Error 500 - Internal server error". I guessed that maybe it was a problem with my theme (I use MYSTIQUE -- I'm not sure of the version) so I changed it to the WordPress default theme and everything worked fine. Well once that worked I decided to try to reactivate Mystique. I was able to get it back up working with all the plugins but NOW I'm locked out of my admin/dashboard.
I can't go in to change the theme back or deactivate the plug-ins. Effectively I'm locked out of my blog while it looks fine from the outside. Can anyone help with this? I get that my theme must not be compatible with the new WP version but how can I fix this? I also backed up my database before the upgrade. ANY HELP IS GREATLY APPRECIATED. I hope this can be resolved.