Solution steps for WIN7 to install Microsoft .NET Framework 4:

1. Click Start - Enter services.msc in the Run box and press Enter;

2. Select Windows Update, right-click and select Stop;

3. Click Start - Enter cmd in the Run box, select cmd, right-click and select Run as administrator;

4. Call up the command window, enter net stop WuAuServ, and press Enter;

5. Click Start - enter %windir% in the Run box and press Enter;

6. Find the SoftwareDistribution folder and rename it to SDold.

7. Click Start - Enter services.msc in the Run box and press Enter;

8. Select Windows Update again, right-click and select Start, then install Microsoft .NET Framework 4 normally.