HTTP 500 Internal Server Error
If you are facing this IIS error with either of the following events, this post might help you in resolving the issue.
1. The server failed to load application '/LM/W3SVC'. The error was 'The specified metadata was not found.
2. The server failed to load application '/LM/W3SVC/1/Root'. The error was 'Class not registered
a) Make sure Ditributed Transaction Coordinator service is running. If you are facing problem in making it work, this link might help. In brief, start the service using service MMC; run msdtc -resetlog if it fails. Check your application again. If you are fortunate enough, your problem might have resolved. If not, follow next step.
b) Follow the following steps. These steps have been taken from this site.
This error is caused by the component services on the computer. To resolve the error
Click Start menu (Windows) - Settings - Control Panel.
Double-click Administrative Tools.
Double-click Component Services.
Expand the Computers folder, open the My Computer folder, and select COM+ Applications.
If an error occurs when you try to open the My Computer folder, refer to the following Microsoft article: http://support.microsoft.com/?id=301919
Delete the following IIS-related packages contained in the COM+ Applications folder:
IIS In-Process Applications
IIS Out-of-Process Pooled Applications
Open Windows command prompt, navigate to %windir%\system32\inetsrv directory and enter the following commands:
c:\> rundll32 wamreg.dll, CreateIISPackage
Note: This command is case-sensitive.
C:\> regsvr32 asptxn.dll