It's been a while since i've done anything with the admin account so i hope i'm not talking complete nonsense! But to boot in safe mode:
Restart your computer, then basically as it starts hit F8 a few times. You'll know you've been successful because a menu will appear with a few options, choose safe mode. (If the windows icon appears before you get that menu you've missed the window)
Once its booted up you should see the blue windows logon screen with your account, and a new "Administrator" account.