>>That won't work if the user hit the off button on the computer without quitting Windows.
>>
>True. I have that when the user clicks the close box x on teh form. Thanks.

Each station can create and keep open exclusively a file with a name such as SYS(3)+'.usr'.

When a new station comes on it tries to delete all such files, then counts how many are left. If user is still connected the delete will not erase the file, but if accidentally terminated, his file will be deleted. This way you can get a reliable count of users if you use a unique extension.