I have set the home directory to be D:/web/asp. And there is a default.asp. If I just type www.abc.com, the page cannot be shown. But if I type www.abc.com/asp, the pabe shows correctly. Is it because the default page can not be asp?
I don't have IIS6 to check, but it sounds to me like your default page works ok (and yes, a default page can be an asp page). Maybe your virtual directory mapping isn't really making the webserver's home folder the /web/asp folder