Win 8.1, no mouse in the game panel

[Flyby]

Fired the old dog up for giggles and grins, but can't get my mouse to work so as to select missions, options, etc. Tried changing compatibility mode to Win7, but no joy. I had the sim working in Win 8.1 before, but it's been a while, and something must have changed somewhere. I checked Task Manager, and saw that there was no "not responding" notation next to it/ Need a little help.
thanks! Flyby out