I spend a lot of time cracking passwords! No, not for stealing software or information, for doing computer repair!
One of the most common home or small business computer service repair calls I get is that Bob, fill in the blank here – lost his password / forgot his password / left the company and never told anyone his password, and we can't use the computer or software.
If you have physical access, most times you can reset a password on any version of Windows XP. Some vertical applications get a little trickier but I still can usually figure out a way to get in to clear the existing password and then let the customer reset it.