If Mike's suggestion doesn't work, this is one I use on my travels, inprder to circumvent the password (legally- lol) doesn't always work but the success rate is good.
Boot into Windows 7 computer.
Kepp pressing F8 to enter the Boot Options Window.
Choose Safe Mode with Command Prompt and Enter.
A Command Prompt will eventually appear. Type net user in the Command Prompt and Enter.
All the user account names will be listed for you. This should be sufficient for you problem, but if in difficulties, you can reset the password.
Type netuser davehc xxx and Enter. (See note below).
When the command says that it was completed successfully,Your new password has been successfully entered, and...