Are all of your drivers updated properly? I know a lot of times with the windows upgrades the drivers updating is a nightmare. I would certainly look into updating display drivers, webcam drivers, and all windows updates, as well as directx to the newest release as well as java and skype. A few posts I've just read also got fixes from using the Microsoft FixIt tool. If you carried over programs from your previous installation of Windows 8, then you could be running into issues from bad registries. For this, I would suggest uninstalling Skype, and running something like CCleaner to clean out all the old pragram data from the previous installations, then re-install the most current version of Skype.