Jens,
I will definitelly read and try to understand the UDF (and all your links) as soon as I have some free time. Rigt now I am under pressure to fix immediatelly what was screwed up.

Is there a way to create a new text file and write to it system environment variables? Such as if workstation's subnet and default gateway equals to the value specified, write to the file:
%username% + %location% on a separate line.

This will tell me whose PC was affected. TIA