Please pardon the sorry state of the formatting in these forums, Maria.
- Use the .NET Framework Setup Verification Tool to verify the installation status of .NET Framework 4.
- If the tool reports can not verify it's installation, try to repair Microsoft .NET Framework 4 in Control Panel > Programs and Features > click on Microsoft .NET Framework 4, then click Uninstall/Change on the Menu Bar.
Wait until the window loads then choose the Repair option.
If it can not be repaired, then uninstall it.
If it can not be uninstalled due to it being corrupted or damage, run the .NET Framework cleanup tool.
- If no program, application, or web site requires that .NET Framework 4 be installed so that it can function, then you have no need for it nor the ongoing issues that are associated with keeping it updated.
If a program, application, or web site has informed you that the .NETFramework 4 must be installed so that it can function, then suggest you download, save, and install the .NET Framework 4 Standalone Installer with all programs being closed.