Repair .NET framework
Run .NET Repair:
Microsoft .NET Framework Repair Tool
If You still have issues:
Please run the System File Checker (sfc) with these steps:
- Click the Start orb and then type cmd in the Search programs and files field.
- In the results area, right-click cmd.exe, and then click Run as administrator. You will be prompted to type the password for an administrator account. Click Continue if you are the administrator or type the administrator password. Then, click Continue.
- At the command prompt, type "sfc /verifyonly", and then press ENTER. This will just scan the system. If it finds issues and you need to repair, run "sfc /scannow".
The scan may take some time, so be patient. Windows will repair any corrupted or missing files that it finds
ONLY FOR NovaBACKUP PC (formerly 'Professional').
If that does not help:
Use this utility to Fix / Repair windows Problems
It is a free Utility that can repair Windows components.