Pac3Man,
Have you tried booting in safe mode by pressing shift as soon as you start up? This is one way to troubleshoot your admin login.
Or, if that doesn't help you figure out what the problem is you can create a new admin account by:
Reboot
Hold down the apple or command key +s after you hear the chime
When you get the prompt enter, pressing return after each line:
mount -uw /
rm /var/db/.AppleSetupDone
shutdown -h now
This will create a new admin account and you can delete the old one or whatever.
Hope this helps you out
CK
custom USB drives