In MMC for IIS (usually accessed through Start->Programs->Administrative Tools->Internet Services Manager), right-click your website, pick Properties, and go to the Home Directory tab. Once you're there, you should see an Application Settings area, with a Configuration button. Click it. The first tab is App Mappings. Find the requisite file extension (aspx) in the list and check its Executable Path. It should be something like this: C:\WINNT\Microsoft.NET\Framework\v1.0.3705\aspnet_isapi.dll If it's not, or it's not there, then you'll have to add it yourself. If there's another file ext there with the proper exe path, you can hit the Edit button and copy the path, then create a new one for .aspx and paste the path in. After that, come back and let us know what you found. Cheers, Peter From: "Casey Crookston" casey at thecrookstons.com These may sound like silly questions, but 1. Does your page have an .aspx extension? 2. Have you installed ASP.NET on your server? If both of those are "yes", then it sounds like someone may have tampered with the ISAPI mappings for IIS. These are not silly questions. Yes. Yes. The only thing I have been able to learn from Google is, just as you have confirmed, is that this has something to do with the ISAPI mappings. But, where on earth do I go from here?