On the other hand, if you just installed some Windows updates and now you can’t open Metro apps, you may have to uninstall those updates. You can do that by going to Control Panel and then going to Programs and Features.
Click on View installed updates and you’ll see the list of updates show up on the right hand pane.
Remove the updates and then see if you can open your Metro apps now.
"Windows 8 Tips-- Windows 8 Metro Apps,Remove an Update"
Reference : online-tech-tips.com