The next step in the Offline NT Password & Registry Editor process is to select the partition that contains the Windows installation that you want to delete a password from.
If that's the case for you, just press ENTER to accept the default partition. Otherwise, type the number corresponding to the correct partition from the Candidate Windows partitions found list and then press ENTER.
Tip: If more than one partition is listed and you're not sure which one to pick, chances are the larger partition is the one with Windows installed.
Windows 7 Note: Every Windows 7 PC will have more than one partition listed. In many cases, the right partition to choose will be number 2. The 100 MB partition labeled BOOT is never the right choice.