Sometimes Windows cumulative updates can mess up something that was previously working. The opposite is also true, in that your software updated and depends on a Windows update that hasn't been installed yet. Try checking your Update History to see if Windows installed any updates around the same time that you started to experience your issue. Specifically check for .NET Framework updates similar to the one in the picture below. These updates can be listed under "Quality Updates" or "Other Updates", so check both drop-down lists.
If you believe one or more of the updates could have caused your issue(s) then you can uninstall the update(s) by clicking on the "Uninstall updates" link at the top of the page. This will bring up a new dialog box, and this will be where you can uninstall the update(s). Make sure you are uninstalling the correct update(s) by using the Update History dialog to cross reference the number and date of the update(s). You are also able to reinstall these updates by finding them on the Microsoft Update Catalog (link included below).
Microsoft Update Catalog