A few people have asked me how to reset the local admin password on a machine if you have forgotten it. There are various way, if you are a domain admin, and the machine is still on the domain, you can do it that way, but if all else fails you can use Petter Nordahl-Hagen’s offline password editor.
You could get in trouble for doing this if it’s not your machine etc, so be careful. If you do this on one of my machines, I will hurt you.
Download it here.
A link to his site can be found here.
Burn the ISO to a disk, stick it in the drive and pretty much just use the default settings. It’s well laid out and towards the end you will get an option to either clear the password or change it to something you specify.
PS – Another option is to use Orphcrack.