If you have a un-registered file type and want to view it instead of having to select Open With. Use Explorer's Right-click and add your program to the right-click options by:
1. Open RegEdit
2. Go to HKEY_CLASSES_ROOT\Unknown\Shell
3. Right click on "Shell" and create a New Key and name it "Open "
4. Create a New Key under the "Open" key you just created and name it "Command"
5. Set the (Default) value to the path and filename of the program you want to use to open the file type
6. For example: C:\Windows\NOTEPAD.EXE %1
You must use the "%1" for this to work.and a space between the exe and the %1