Hello Joanna,

Please try to repair the .NET Frameworks by following this procedure to see if this helps:

To repair the .NET Frameworks 3.5 and 4 you need as first to use following cleanup tool to remove .NET 4:
http://cid-27e6a35d1a492af7.skydrive.live.com/self.aspx/Blog_Tools/dotnetfx_cleanup_tool.zip
Once done go to Control Panel then choose Programs and Features and then click on Turn Windows features on or off. Clear the check box for Microsoft .NET Framework 3.5.1 and then click on OK. After Windows disables the feature you will need to go back to re-enable Microsoft .NET Framework 3.5.1
This procedure can take some time to deactivate and activate .NET 3.5.1 and once done reinstall .NET 4 after downloading it from following link:
http://www.microsoft.com/en-us/download/details.aspx?id=17718

Please keep me updated.

Hi,

Windows has something called System Recovery. If your system is set up to create restore points, then you might have one to a date when it was working. Normally when Windows gets an update, it will create a System Restore Point and they are very handy when you encounter problems.

As usual, always backup all important stuff even though System Recovery claim not to touch your personal data.

More info can be found here:
http://windows.microsoft.com/en-gb/windows/what-are-system-recovery-options#what-are-system-recovery-options=windows-7

Regards
Kenneth