|Could use a barts/ubcd4win disk to access restore point maybe.|
Could use any xp disk to "repair" system maybe.
Might use barts to view event logs to see what is going on.
If you think password is the issue you can remove it with tools.
"Best Practices", Event viewer, host file, perfmon, antivirus, anti-spyware, Live CD's, backups, are in my top 10