Why can I log on with new WinXP accounts?
I don’t think you can fix/reinstall the MSI/Windows Installer in XP like you can in 98/NT/2K. Try changing your new admin account – bump the priveleges down. This may not fix the problem where new limited accounts won’t load, but should get you where you want to be. You might also try booting in safe mode and see if you can log in with a limited account (I don’t think you can). If you can, though, then restart in normal mode and log in with the limited account.