To open-up a given custom file extension (.wow for instance) using a given application (say wowViewer.exe) , you need to alter the registry entries (Please make sure that you’ve got a backup before editing the registry) as follows:
- Add a new registry key under HKEY_CLASSES_ROOT.wow
- Set the default value of the above entry to wowFiles
- Add a new registry key under HKEY_CLASSES_ROOTwowFilesShellOpenCommand
- Set the default value of the above entry to wowViewer.exe “%1”
That’s all it takes to open-up a custom file extension using a given application.