.NET Framework 3.5 installation errors

1. Right-click Start, and Click Run

2. Type regedit.exe and click OK

3. Go to the following registry key:

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU

4. In the right-pane, if the value name UseWUServer exists, set it data to 0

5. Exit the Registry Editor

6. Restart Windows