This should work with Windows Vista, 7, 2003 and 2008, maybe more. I personally tested it with 2008 R2 Standard only.
To reset a Windows Admin password, you need the following things:
- Physical access to the Server
- A Windows installation boot media
If you have it all, continue with this:
- insert boot media and reboot (from media)
- jump through the menu so that you get a recovery console at the end
- find the original installations C:\ drive and change to it (original C:\ drive can be D:\ or any other letter when booted from recovery/install media)
- then:
cd Windows\System32\ copy sethc.exe C:\ <-- remember: C:\ could be D:\ now!! copy /y cmd.exe sethc.exe exit
- reboot your box
- on login screen, press shift-key five times
- a command window should show up
- maybe you have to press Alt+Tab until the new window has the focus
- type:
net user administrator <new password> <-- while <new password> is actually replaced by your new password :) exit
- login with your new password