So, somewhere along the way, I unknowingly installed something (VoyMedia? Whatever that is?) that took over associations for just about every multimedia file type, including, it seems, CD autorun, even for CD-ROMs. I've restored most of these from another relatively fresh W98 installation by backing up the relevant registry entry, including other CD media like audio CDs, but CD-ROM autorun still doesn't seem to be working, and I can't seem to find a similarly clear association entry for CD-ROM autorun in the file types list, nor in the registry.

How can I restore the association so that my CDs will autorun again?
I need to know either the right listing in the file types settings, the right entry(/ies) in the registry, or perhaps another specific way to reset only this part.
I'd rather not do a whole fresh Windows reinstall just for this, ideally; I'm quite set up with a lot of customisation and games installed that would take a long time to reinstall and reconfigure.

(And just to stave off the obvious question, yes, "Auto-insert notification" is ticked in the Device Manager properties for this CD/DVD drive).