Right-click on the file and select “open with”, then “show apps”. Scroll to the bottom of the list and choose “look for another app on this PC”. Browse to C:\Windows\Microsoft.NET\Framework\v2.0.50727\ and click the file that says “RegAsm.exe”. You will see a brief Windows DOS command flash on the screen. That’s how you know it was registered successfully. You only have to browse to that file the first time you do it. After that, you can just right-click the next file you want to register and select “open with” and you will see “Microsoft .Net assembly registry” in the list of available apps to open the file with. You just need to select that option and it will register the file.