Hi Vinod Choudhary,
You cannot have McAfee when you use a proxy for the internet.
To remove you're proxy settings do this:
1. Please open Internet Explorer and click Tools -> Internet options.
2. Please click on Connections tab.
3. Click LAN Settings… and a window named LAN Settings will open.
4. Please uncheck all options and click on Ok.
5. Please close Internet Explorer window.
Vinod – your University’s internet connection may be an secured one that’s the reason you are unable to activate them, if you are using a laptop try to activate them by using a different internet connection.