I can't run Windows Store apps after upgrading from Windows 7 to Windows 8
If you've upgraded your PC from Windows 7 to Windows 8 and you can't run apps from the Windows Store, it is probably because you have a 3rd party antivirus app on your PC that is blocking the new apps from running. Try upgrading your antivirus app to the latest version available. If that doesn't fix the problem, try uninstalling and then reinstalling the antivirus app.
If you're still unable to run apps, run the Apps troubleshooter. This tool can automatically fix some problems with apps. The troubleshooter will work on all languages but the text in the troubleshooter is only in English.
If one or more of your apps from the Windows Store won't open and displays an "X" on the tile on the Start screen, try uninstalling and reinstalling one of the apps that won't open.