IIS – Internal Server Error, Class not registered

On one of the Win XP Professional machines IIS was throwing an Internal Server Error. When I checked the Event Viewer, there was a “Class not Registered” error and following was the content of the event:

Event Type: Warning
Event Source: W3SVC
Event Category: None
Event ID: 36
Description: The server failed to load application ‘/LM/W3SVC/1/ROOT. The error was ‘Class not registered’.

Bare bones: ASP and ASPX pages were not being recognised and http 500 error was returned to the browser.

I was able to google my way to the fix on Bernard’s MSMVP blog and God it made my day. Here is the working solution, its not my solution but I felt the need to document it and to share.

I was able to fix this issue following these steps:

1) Open Command Prompt and type “cd \windows\system32\inetsrv”
2) Run “msdtc -resetlog”
3) Run “rundll32 wamreg.dll, CreateIISPackage”
4) Run “regsvr32 asptxn.dll”
5) Run “iisreset”
6) Reboot…

Reference:
1. The famous ‘Class not registered’ – Bernard’s MSMVP Blog