We are running 3CX on our Windows 7 machines and it works just well. But there is one thing, that gets a bit annoying over time. The volume-setting for 3CX in the windows audio mixer won't be retained. First i thought, this might be a problem with the Audio Mixer itself, but i figured, that it would store volume settings for other programs just fine. Only the volume for 3CX is set to default again, everytime the program will start.