You can use NTPASSWD to reset the admin password or try booting SAFE MODE (widely documented) and trying the administrator account to change your password.
I need help getting past the windows 7 startup password on my laptop. It wasn't there before, but this morning I tried getting on and it won't let me enter safe mode or the boot menu. It's a black screen with a blue rectange that says "enter current password" I have tried doing the ctrl alt delete thing and F2, F8 and F12.. But nothing works! Help!