ASP.NET: HOW TO RE REGISTER ASP.NET VERSION # IN IIS‏

1. Open command prompt. Navigate to the following path:

<drive letter>:\Windows\Microsoft.NET\Framework\<version #>\

2. Run following command to un register ASP. Net version #.

aspnet_regiis -u

3. Run following command to register ASP. Net version #.

aspnet_regiis -i

That's all you need to do. Have a nice day :).