Hi there, I've been using VirtualMIDISynth since I first found it last year and I love it (I'm also always recommending it to others). I mostly use it to beef up the music of old video games. However, recently I also started using MUNT for some games which were mainly designed for Roland MT-32 hardware and switch between VirtualMIDISynth and MUNT quite often - actually VirtualMIDISynth would be perfect to manage that one too since Windows Vista/7 doesn't allow you to easily change the default MIDI device and your tool does it perfectly (it's much more convenient than any other tool I've found for this). However, there is one problem: Both MUNT and VirtualMIDISynth automatically use the same registry key (midi1), installing one of them will always overwrite the other (and I guess this may also happen with other MIDI devices that use that key). So the only way to use both is to manually move the MIDI device that was installed first to midi2 or another key (which is both awkward and kinda dirty since uninstalling MUNT or VirtualMIDISynth will probably reset the wrong registry key). I'm wondering whether you could make your installer check whether midi1 (or any other key) is being used by another MIDI device already and make VirtualMIDISynth use one which is still free (one with the value "wdmaud.drv"). This would make it much easier to use VirtualMIDISynth together with other MIDI devices and as a management tool for multiple MIDI devices.
Btw, I think this problem didn't occur on Windows XP, it seems that there I could install both MUNT and VirtualMIDISynth without the other one being overwritten although I'm not completely sure.