1. Download the Userenv.dll file from any free DLL download website (see the 'Resources' section of this article).
2. Right click the downloaded DLL and select 'Copy.' Click the 'Start' menu, select 'Computer,' open the 'C:' drive. Double click the 'Windows' folder and the 'System32' folder. Press the 'Ctrl' and 'V' keys at the same time to paste the file into the folder. Click on 'Yes' in the confirmation pop-up to replace the existing bad DLL (this message will come up only if the DLL is corrupt, but still present in the system.)

3. Go to the 'Start' menu, type 'run' in the 'Start Search' box and press 'Enter.' Type 'Regsvr32 'C:\Windows\System32\msxml3.dll' in the 'Run' window's search field and click 'OK' to register the DLL. Click 'Yes' in the pop-up to confirm the registration.
4. Restart your computer.