I recently used this method to get back on my computer because i forgot the pass its really simple and only takes about 5 minutes
Ok so if you are locked out of the computer and you don't know your pass the first reboot the computer and for my computer you press the f8 key to go to this thing that i dont know what it is then go to safe mode in command prompt then it will take you to another screen where it says something about Microsoft whistler or something choose that (only option) then it will take you to the login screen where you enter the password for your user account on that computer but it should also have THE Administrator account choose that one (has snowflake for a picture) then it will go into safe mode with a command prompt there type net user it will show the accounts that are on your computer find the one you want and type net user "user" (put the account you want between quotations) then * hit enter it will prompt you to type new password and then retype password do this then reboot your box and your in
NOTE: I think this works on all windows platforms but im running off XP so i dont really know the complete code is net user "user" * then press enter
this assumes that the admin account has not been passworded
