Honestly, it will be quicker to fully uninstall PRMumble 1.0.0.4 Beta , reboot, and reinstall, than to try to troubleshoot this any further.
H. UNinstalling and Reinstalling
Uninstall PRmumble, and delete its configs. Easiest way is to use Win+R and type "%appdata%" and press enter.
It will open "C:\Users\[Username]\AppData\Roaming\"
Now lookup for folder named Mumble there and delete it. Reboot and Reinstall the newest PRMumble
Exactly what did you upgrade? If you upgraded your GPU, and/or monitor, and/or changed resolution, you might have one of a few problems:
Just in general,
make sure you deleted all prior GPU drivers, (especially true if you swapped from an AT/AMD GPU to a NVidia card)
In the PRMumble overlay options, make sure the overlay is actually onscreen, and not off the edge
Another way to test this, which I just recently figured out, is turn on PRMumble and connect to a public server in the Server->Connect menu, and then start any other DX9 game, and see if the overlay works.
That will make a binary choice, if PRmumble works, than it's a PR.exe problem, if PRMumble crashes, it's PRmumble problem. BUT, I suggest a fresh reinstall first,... all of the testing takes much longer than a reinstall.