Thank you for taking the time to try and help me - sorry it took a couple days to get back to you. To answer your questions:
- Selecting Disable Speech Recognition did not stop the issue
- Running Windows Speech Recognition did not have any lockup issue
- I couldn't get Ctrl-Alt-Delete to respond either
I do have more clues though. By luck, I happened to notice that while my keyboard was locked up, another different wireless keyboard was still working! So I moved the USB transmitter for the locked keyboard from a USB hub to various other direct USB ports and found that if I plugged into the front of the machine, it works. However, that location doesn't work for me (my desktop machine is too far from my flight sim rig). I tried a rear port and it didn't work, but if I put a non-powered USB hub between the rear port and the keyboard, it works almost every time.
I decided it must be some issue with USB hubs, so I eliminated two of them and bought a brand new powered 10-port hub. The keyboard still has to be in the janky unpowered-hub-to-rear-of-PC config to work though.
However, now the problem has moved to my trackball. Every time I select the headset mic in Voice Attack my trackball locks up! The even weirder thing is that if I switch VA to a different mic, close the app completely, rerun it, then switch mics to my headset it works perfectly. I can speak commands and it responds as I'd expect (perfectly, even!). Then, the second I run DCS, everything freezes again until I unplug my mic.
I also have the problem where if I set the target to "current window" and play with VA just in Windows, it always fires up the VA PDF file. I saw someone else complain about this behavior and never saw an answer. I have no idea if it's related, but I change the target back to DCS to avoid it.
I have uninstalled VA and reinstalled it and see no difference. Could it be my microphone is defective and somehow causing all this? I've never used this mic before.
Sorry for typing so much. I appreciate if you actually got this far.