Dot Net Framework 4.0 Installation Error

1: Click Start > Run.
2: Type cmd and press Enter. Please run the following command in the opened window.
net stop WuAuServ
3: Click Start > Run Type %windir% and press Enter.
4: In the opened folder, rename the folder SoftwareDistribution to SDold.
5: Click Start> Run type cmd and press Enter. Please run the following command in the opened window. net start WuAuServ

Now You can try to install Dot Net Framework 4.0, Good Luck :)