Odd problem with Session Drummer 3 Sequences

Greetings, all I've got a problem that's got me scratching my head regarding Session Drummer 3. Everything functioned properly until I had a soft synth (not SD3) lock up. Until now, all I've had to do is close Sonar, and re-open it to get it all working again. However this last time was different. I have a MIDI track linked to the SD3 (12) tracks, and those linked to the drum buss. Thing is, now all I see is the MIDI track jumping, but nothing happening in the separate drum tracks. It's not being converted from a MIDI signal to a digital/analog signal. There's a few more oddities that are happening, too. I've tried to create a new project and insert SD3. I've opened projects that have (or had) functioned properly. The same thing happens. When previewing a pre-made drum pattern, there's no sound and the drums in the SD3 synth window doesn't move. When the SD3 window is open, I can click on the drum kit and see the kit pieces move, but no sound. Now here's the odd thing... All the other soft-synths appear to work fine. I've checked and rechecked everything. Projects that worked earlier don't have SD3 sound now. I've uninstalled Sonar, cleaned the drive (and registry) of all traces of Sonar I can find, and reinstalled... Still no sound. This one's got me stumped. I could use a bit of help. Thanks, in advance