ASP Pages cannot be displayed error 404

[A]

I get this page cannot be displayed every time i try to run ASP pages on Win
2k Server IIS5.1

I know that the guy who's server it is had run a couple of lock down tools
after his server's security was compromised. Could this be part of the
reason why? I had a look at his configuration and .asp files were pointing
to 404.dll? I changed it to the asp.dll in inetsrv directory but that didn't
help as well as restarting IIS.

Any other sugestions as to what could be going on? Anything else i could
try?

Please help. Thanks in advance

A