OK. I'll give it a try. ThanksI only have 7.5, but assuming what you have is similar, you can delete all the settings and start over by removing the Realflight 7.5 folder from your documents. When you fire it back up the sim makes a new folder.
I would simply move it somewhere and save it. From there you can reload all your planes and everything starts from default.
This works on 7.5, but I now sure about other generations. If that doesn't fix it, you can always move your original Realflight folder back into documents.