RC4 was working fine, now all of a sudden it is asking for a key #. I put it the original I got several months ago but it does not seem to work any longer??? I upgraded a few weeks ago to 4.1 and it went smooth. My FS9 ATC is no longer working also????Can anyone help me out?

Something on your system has changed causing Radar Contact to ask for a new key. You should send a request for a new key to [email protected] you checked your Flight Simulator settings under Options|Settings and made sure the ATC options are enabled.It might be a good idea to reinstall Flight Simulator. If you do don't forget to first remove FSUIPC.DLL and AdvDisplay.DLL from your modules folder then after reinstalling Flight Simulator put them back. That will save you the trouble of reinstalling Radar Contact.