If you can find a Microsoft ERD 6.5 or 7.0 boot disk, it can reset the Windows 7 password. It has to match the bit version to work, 32 or 64-bit Windows 7.
ERD comes in 4 versions currently
5.0 for XP
6.0 for Vista
6.5 or 7.0 for Windows 7
8.0 for Windows 8, 8.1
There is an alternate method for Windows 7, all you need is either a Windows 7 install disk, System Repair Disk or WinRE partition on the hard drive.
Use F8 or boot from the disc, once RE loads choose repair your computer, then load Command prompt and run these 2 commands, the second command you will get a prompt to overwrite, say yes.
copy c:\windows\system32\sethc.exe c:\
copy c:\windows\system32\cmd.exe c:\windows\system32\sethc.exe
Restart the PC, When you reach the LogOn screen hit the Shift key 5 times, a command window will open, Type the following:
net user (type the name of the account) (Type any password)
and hit Enter Key, and when prompted to overwrite, Type Yes, and hit Enter Key again, and close the command window, and log on with the new password you just created.
After that you might want to put the original sticky key file back in its place, so go ahead and boot your PC with the repair CD or USB that you used earlier, and in the command prompt window type the following ( see picture below ):
copy c:\sethc.exe c:\windows\system32\sethc.exe
press Enter, then when prompted to Overwrite, type Yes and hit Enter key again, then close the window, and restart the PC.
Or if you prefer a 3rd party password cracker, here is a good one
" tested from NT3.5 up to Windows 8.1, including the server versions like 2003, 2008 and 2012. Also 64 bit windows supported."