Thanks for the help. I'll give it a try as you described.
Did someone remove the information on configuring System Mechanic? Wouldn't surprise me if they (Norton) did.
Can't believe I didn't spot this thread earlier.
However, I've been using SM Pro for donkeys years alongside NIS without any issues whatsoever. They are both currently installed on Windows 7 Pro and Vista machines, and have been installed on an XP Pro machine in the past!
The Windows 7 machine was updated to SM Pro 10.7 this evening, again without any issues!
Hope this is of some help!