HTTP Error 500.21-internal Server error

Handler "pagehandlerfactory-integrated" has an error module "Managedpipelinehandler" in its module list

Error reason: VS2010 default is the 4.0 framework, 4.0 of the framework is independent of the CLR, and 2.0 of the difference, if you want to run 4.0 of the site, you need to register the 4.0 framework with aspnet_regiis, and then use the 4.0 class pool, you can run 4.0 of the Web project.

How to register the 4.0 framework with aspnet_regiis:
In DOS specific operations are as follows:

C:\USERS\ZHANGZHU>CD C:\Windows\Microsoft.NET\Framework\v4.0.30319

C:\windows\microsoft.net\framework\v4.0.30319>aspnet_regiis.exe-i
Start installation of ASP. NET (4.0.30319).
...................................
ASP. NET (4.0.30319) installation is complete.

Transferred from: http://www.cnblogs.com/zhangzhu/archive/2012/05/10/2495000.html

HTTP Error 500.21-internal Server error (RPM)