I just stumbled upon very essential information that I didn't know before, or at least wasn't sure it's true. that information can solve numerous problems, thus i'll post it here. if you see such information, feel free to post it here as well.
and now to the point:
ASP Pages, Session State and the Parent Path options are disabled by default in Windows 2003 Server. If do not enable this functionality after installing IIS, IIS returns a 404 error. You can enable these features through the IIS Manager. To enable these options: