Based on the description, it appears that you are having issues with Apps and are not working normally. I will be happy to help you with this issue.
1)Have you made any changes on the computer prior to this issue?
Check if you have the following settings in your computer:
• 1024x768 is the minimum screen resolution needed for Metro apps; they will not start when your resolution is lower.
• Check if UAC (User Account Control) is enabled. UAC must be enabled for Metro apps to work.
To check, simply type UAC from the home screen and it will appear on the Settings search result.
• Try using a local account instead of a Microsoft account (Live ID) and check if the issue persists.
If you have above settings and if the issue still persists, you may perform the steps mentioned below and check if it helps.
Method 1: Right click on the desktop, select screen resolution, check if the resolution is set to 1024x768. If it is not set to
1024x768 change it to 1024x768. It is the minimum screen resolution needed for Metro apps; they will not start when your resolution is lower.
Method 2: I would recommend you to run the app troubleshooter and check if it helps.
Method 3: If you are still facing the issue then I would suggest you to try uninstalling and reinstalling the Messaging app and check if it helps.
Step 1: Follow the steps to uninstall the app:
a. Right click the app that you want to uninstall.
b. Click on Uninstall in the task bar.
c. Then click on Uninstall button.
Note: Once you uninstall Messaging apps all these apps will get uninstall automatically Mail, Calendar, People and Messaging once you install any one app in Mail, Calendar, People and Messaging all four will install automatically.
Step 2: Follow the steps to install the Microsoft apps:
a. Click on Store in Windows 8 User Interface page.
b. Search for the app that you are looking for and click on the app and install it.