Boot UBCD 5.0.3 and select Parted Magic. Then boot from RAM (first option).
Then once in Parted Magic find the tool "PCLoginNow" should be under Menu>>System Tools. This will let you reset/change or even clear the password without any command line knowledge or having to worry about if you did it right. After you are finished reboot and log in to windows.
Visit the UBCD Wiki: http://wiki.ultimatebootcd.com
Please check your UBCD
ISO MD5 Hash Sum
; May prevent issues later on by not having an exact copy.
Currently Working on Common Issues and Repair Tips
on the Wiki.