Hmmm that is very strange. Installing the full version shouldn't affect the demo, or vice versa.
If you have already tried all other reasonable approaches, this is what I would do:
- Delete both the demo and the full version from your computer.
- Restart your computer.
- Download the zip file for the full version again (just in case there was some error in the download)
- Unzip the full version, possible to another folder on your hard drive
- Re-connect your transmitter. Make sure you don't have any other joysticks/controllers connected at the same time as that might cause a conflict.
- Try to re-calibrate in Freerider
(As you may know there was an automatic Windows 10 update that rolled out some time ago that broke the USB drivers. I don't think that is the problem on your system though since you were using it without any problems basically just minutes before. I just thought I'd mention it anyway. You can find more information here).