What you can do is log onto a working computer that has a CD-RW drive and internet access. Download a program that is called OPHcrack. This download will be an ISO file. Burn a bootable copy of the ISO file. Once the burn is done, then return to the computer that you are locked out of. Have your computer boot from the CD rom drive with this disc in it. OPHcrack runs on its own and will crack your PW and any other PW that has been logged in the SAM file on the windows machine, regardless of PW complexity. KEEP the disc for later use if you so happen to need it again.