oskiatl wrote on Jul 10^th, 2013 at 1:42am:

People, did you completely unistall all of the 777 components from your hard drive and FSX folder,did you reboot after install? If you did all of the above things then do it again, but before you reinstall this time clean your registry with a cleaner then reboot.

I agree with this. :)

I uninstalled the old version> deleted the registry entries > cleaned out any folders after backing up stuff if I want to keep (like texture.XXX folders) > REBOOTED my computer > Reinstall v1.2 > REBOOTED my computer. Everything should be working properly after doing that. It certainly seems to be working fine for me from the couple of flights I've done.

Clearing the entries from the registry is not essential, but worth considering (I always remove it).
Because I'm using my Manual Offline Activation key_xxxx.txt file to reactivate it, the amount of FULL reinstalls I do is not affecting my Profile Activations (it's only seen as a single activation when given the key_xxxx.txt file), which can lead to a locked product from too many activations.