They weren't installed under Win7 so Win7 can have no "knowledge" of file locations and settings. The programs themselves are providing that information when they run.
- thanks Ping - therein lies the problem - does Win7 call on the XP OS to track down the dlls via the registry and so on?
Leaving the OS in place may well be the choice (poor Mixture....
) but I would have thought a VM would be a better and safer option. Otherwise how to ENSURE that no internet access reaches any part of XP?