How to find forgotten user password?

[melopll]

Hello, I am running XP SP2 and I am sharing a printer on the network. The printer is connected through USB port.

The other machine is running SIMPLYMepis and it seems that with SP2 an official login is required. How can I see what is the password for the Windows user? At login is automatic, I don't type any password, but to setup a printer...
Seems Win is getting better... cheers.
Thanks