Hi, I have a C# Windows applicaiton that runs on Windows 2000 server or higher. Users saves a couple of text file in my applicaiton that I give it a special file extension. I would like to write a C# dll that would register this file extension (for example .abc) in the registry. I would then use this dll in MSI installation's customer Action to execute after installation is completed. Also, how do I indicate this file type to be "NoOpen" type unless it's done by my application using stream reader? Thank you.