Hmmmm....Here's what I would like you to do.... We need to correct any errors or corruptions in the Win 8 files and Metro.
Please bring up an elevated Command Prompt. This can be done by one of two ways:
First, go to the "All apps " screen from Start. Find the Windows system Group on the far right and right click Command Prompt. Choose run as administrator on the pop up charm bar at the bottom. This will take to the Desktop. There please enter the following in the prompt window:
sfc /scannow (make sure there is a space between "sfc" and the forward slash)
Hit Enter. The process will take a while, so be patient.
Second, from the Desktop, place your cursor in the lower left corner of your screen. When the large Start Screen icon appears, do a right click. This brings up a nice pop up menu. Find "Command Prompt (Admin)" and click it. Enter the above mentioned command, and go get a cup of coffee or tea.
When the process is finished, it will tell you that it fixed any corrupted files. Close the window and go to the Start Screen. You should see the icons for Mail, People, Messaging, and Calendar. If you don't see all of them, they are a group from the Store, therefore they must all be uninstalled, before you can reinstall any one of them.
Hope this helps,
John