You can get the name of the logged in user via the NetUserGetInfo() API call, but there is no way to get the user's password programmatically. This is by design, and is a fundamental security restriction of almost every OS known to man. You can, however, test a potential password to see if it is the "real" one, so you could conceivably ask the user for their password, then check it to make sure they didn't lie to you...

Cheers!
Humble Programmer
,,,^..^,,,