rundll32 usage example

Really Old Note

rundll32.exe can be used to start DLL file without executable file. It is very nice if you know what you are doing:

rundll32.exe %SystemRoot%\system32\shimgvw.dll,ImageView_Fullscreen %1
rundll32.exe url.dll,FileProtocolHandler "C:\Documents and Settings\Sergei\My Documents\My Pictures\JumpKeys-1.PNG"

The following is possibly an original source of information.