I had deleted one of the simconnect folders to try and repair it with a simconnect reinstall from the SDK. I royally screwed up the sim however. Your second solution was the only one that worked, a complete windows reinstall. I've done that and everything is working fine as it should. From now on I'm not touching anything in the windows folder!
The SimConnect 10.0.61259 folder isn't in my winsxs directory anymore. Because of this, FSUIPC 4 is failing to load. I have tried repairing and completely reinstalling Acceleration from my install disc. Neither option put the folder back in winsxs. Is there any other way of fixing this?