[MessiAz]

hi, i am windows coder. (no php sorry)
i would like users from a selected usergroup on my forum to use a windows program created by me only if they enter a valid serial number on their private profile fields.

the only way to do this is by entering on the windows program the user's username and password and sending a get/post request to a magic php file on my forum.
the magic php file should get the username and password and auth user, if password is correct it should check if user is from usergroup X, if usergroup is corrent it should read the serial number from their private profile field.

right now im in search of this magic php, but my php knowledge is amost null so i would like to know if there is something similar around here?
if not any help will be welcomed.