I have been running Notepad++, Therion, Survex, PocketTopo, Topparser and Adobe pdf readers on W7 for several years.
The only problems I have had are with Aven & that's down to that program not W7. I have never had a problem with Xtherion not recognising thconfig files without a name extension. I have run all of them under W8 as well, without issues, but haven't done so since the W8.1 free upgrade happened last week, so I'll not comment on that. Graham
