if the iis welcome page does not show up this means that somehow iis cannot
process asp.pages.
so even a helloworld page would not work
No, it means a problem prevented the IIS Welcome page from showing.
There are many reasons that page wouldn't show while a Hello World!
page would.
the error it shows:
Server Application Error
The server has encountered an error while loading an application during the
processing of your request. Please refer to the event log for more detail
information. Please contact the server administrator for assistance.
Finally, a full error message. Though you missed the error code,
likely a 500 error. See:
Why do I get a 500 Internal Server error for all ASP errors?
http://www.aspfaq.com/show.asp?id=2109
Also, did you refer to the event log? If so, post the full event log
error, including source and ID. If not, follow the error message you
received and look at the event log.
Jeff