I have wrote an ActiveX control that manages users on Win NT. It alows you to retrieve/change almost anything about users, including the password, user name, etc., etc.

I can send you a demo copy if it may help you.

Vlad

>On entry to our main application (we use VFP5) I want to change the effective Windows userid and password, then change it back (if necessary) when the application ends.
>
>Can someone please advise how to achieve this?
>
>Is there some API call perhaps?
>
>Thanks