When I start up windows XP it stops at the loading screen where the accounts should appear. Recently I used AVG antivirus and it reported me automatically(without scan) of security threats and I decided to put some of them to quarantine despite of it saying that it might cause computer problems&crashes. After that I used superspyware to remove all threats, and today then the AVG said that it does not have a lisence anymore, so I had to uninstall, and after the uninstall it no longer works/lets me trough the login screen. Hopefully you will be able to help.
sometimes...spyware remover programs delete files they are not suppose to. In this case, some of your AVG files. If i were you i would reboot in safe mode and try to find out wats wrong.