I need to kill an application roughly so I can get phantom subscriber of that application in my database (this can not be produced by closing the application). Manually, if
Karl Peterson's excellent archive of VB6 code has high quality sample code and full explanations using both WM_CLOSE and TerminateProcess. Accept no substitutes!
One pitfall you might see in a lot of code out there is that sending WM_CLOSE to a single window handle you have isn't sufficient - most applications comprise numerous windows. The answer as implemented in Karl's code: Find all the top-level windows belonging to this application and send the message to each.