I wonder if it is the update of windows 8.1 breaking the apps ? As I had Avast 2014 on my system prior to the update and everything was OK…
After my first start in 8.1 3 or 4 apps were broken and I had to re-install them … Skype was one along with freebooks and fresh paint there was another but I cannot recall which one it was
EDIT: I knew I had seen a write up on this about release time http://www.theregister.co.uk/2013/10/17/windows_81_update_what_to_know/