Here is code I tried:
Windows Registry Editor Version 5.00 [HKEY_CURRENT_USER\Software\Classes\DLI\DefaultIcon] @="c:\\dli\\fav.ico" [HKEY_CURRENT_USER\Software\Classes\DLI\shell\open\command] @="c:\\dli\\dli.exe +i %1" [HKEY_CURRENT_USER\Software\Classes\.dls] @="DLI" [HKEY_CURRENT_USER\Software\Classes\.dls\DefaultIcon] @="c:\\dli\\fav.ico"
I assigned new extension to my application. I wanted also assign icon to files with this extenstion, but it doesn't work. File still is being shown with unknown icon.