By default we need to choose apps from tool list to select applications to open unknown files.Below is a simple guide of registry hack about how to add “Open with Notepad” to the right-click menu in windows 7,by this way we can open some types of files fastly,such as .php .bat or other types of files.
1.Open regedit.exe from the start menu or the Run prompt
2.Go to the following path in your registry editor
3.Right-click on “shell” from the left window to create a new key, naming it to “Open with Notepad”. Then create a new key under “Open with Notepad” named “command”. Double-click on the (Default) value in the right-hand panel and enter in the following value:
4.Done.Now you can see “Open with Notepad” in the menu after you right clicking to unknown files.Good lucks.