you need
  • - the right to change the registry.
Guide
1
Run the "Registry Editor."Click on the button "Start", located in the taskbar on the desktop.In the menu that appears, select "Run".Open dialogue "Run."In the text box "Open" enter redegit.Click OK.
How to register a file type
2
Register file extension and map it to the symbolic identifier type.In the left pane of the Registry Editor, select the root partition named HKEY_CLASSES_ROOT.Create it with the name of the key corresponding to the recorded file extension type.To do this, click on th
e name of the key, right-click or click the "Edit" menu.Next, select "Create" and "Section".Enter the extension, including the dot (for example, .myapp) and press Enter.

In the left pane, select the newly created partition.In the right pane, double-click on the item that is named "(Default)".In the dialog box that appears, enter the ID of the registered file type.It can be anything, but must be unique.It makes sense to give simple and catchy name file types.
How to register a file type
3
Register file type.In the HKEY_CLASSES_ROOT create a key with the name corresponding to the name of the type introduced in the second step.To create a registry key make steps similar to those described earlier.The parameter default created partition, enter a brief description, characterizing the information that is stored in the files of the registered types.
How to register a file type
4
Assign an icon file type detected.Create a key named DefaultIcon section added in the third step.The default value of this key, enter the path to the file icon, the executable or DLL.In the latter two cases, after the file name separated by a comma, you can specify an image resource identifier contained in the module.
How to register a file type
5
Determine the application that opens files of type.Add a key with the name of shell section type of file.Add in the shell key key named open.Next, add the key in the open command.Thus, the registry should be created branch type HKEY_CLASSES_ROOT \ imya_tipa_fayla \ shell \ open \ command.

Change the default key command, typing in a command to start an application that can open files of the registered types.Use 1% placeholder to indicate where the name of the file to open substitution in the command line.
How to register a file type
6
identify applications, edit files of type.Perform actions similar to those described in the previous step to create the registry branch HKEY_CLASSES_ROOT \ imya_tipa_fayla \ shell \ edit \ command.As a default key command, type the command to edit the file.Filler 1% may also be used.
How to register a file type