Restart your computer with the windows installation disk, then boot from that CD the same way you did with the OPHcrack CD.

Click next, repair your computer, select OS(usually only one), command prompt

then type

regedit

then hit enter.

click, but do not expand, the HKEY_LOCAL_MACHINE. It should turn blue. then go to file, load hive.

navigate to this file path (first click the computer symbol to the left)

C:/windows/system32/config/SAM

a target name box will appear, make sure you type this

Target SAM

then expand the HKEY_LOCAL_MACHINE, the Target SAM name will appear as a folder, expand it
expand the following
SAM
Domains
Account
Users

click on 000001f4 (administrator account)

click in front of the 11 , it should look something like this

11 |

then hit backspace and type 10

close everything and restart your computer without any CDs and the administrator account will be there.