There is no sidebar.exe for Win 8 by default, and as your files not associated to anything, why should they run. It´s not a task you start that simple. Only chance: use an Installer as Tito suggested .
I installed 8gadgetspack on surface pro with win8pro They worked fine! After the update to win8.1 pro via the store, just freeze! The same result after uninstall and new install again! A new clean install of win8.1pro, brought the same results! Any suggestions???