I have had two different problems that gave me a "NO KEY" error. In one case, my system clock was set way out of date. It was set to the year 2031.
In the other case, the program was unable to access the C:\windows\prefetch\ folder. Neither of these problems was with FE though. The last one I had to get help from Microsoft to fix. FE uses the prefetch folder more than any game I have ever encountered and it seems to be their principal error tracing strategy.