running .asp files

We are running nt 4.0 and used iis 2.0 to try to allow asp files to execute (by modifying the home directory to execute permissions). Yet, when we hit an asp page (from our server) the browser does not recognize it and attempts to try to download the file. Is there some place where we have to install something to allow asp files to execute? Is this not an automatic setting? Is there another setting that we missed? How can we troubleshoot this problem? Help! Thanks.