Posted Wed Apr 14, 2010 3:44 PM
Usually this happens if you use a keyboard shortcut to take focus away, for example, Alt+Tab -- Classic99 sees the alt and the tab down events, but Windows never delivers the up events because it doesn't have focus anymore (now that I think about it, it would be easy to clear the keyboard state when focus is lost, let me take a note on that and I'll code up that fix).
If you are running CPU overdrive, the keyboard repeat delay ends up way too short, and my workaround for that doesn't work in Extended BASIC, so you get massive keyboard repeats, although that at least should respect the keyboard.
There's no explicit reset built-in, but tapping the key that is repeating should stop it. Tapping Enter should clear any stuck meta-keys (control, alt, shift).