Author: Jonas Bilinkevicius 

How can I close an unwanted popup window using its partial title? I have tried 
destroywindow, however, it cannot close the window I want to close.

Answer:

Well, first you need to get a handle to the window. The following code can find a 
window by window title (even a partial title, and is case insensisitive) .
1   
2   function HWndGet(partialTitle: string): hWnd;
3   var
4     hWndTemp: hWnd;
5     iLenText: Integer;
6     cTitletemp: array[0..254] of Char;
7     sTitleTemp: string;
8   begin
9     hWndTemp := FindWindow(nil, nil);
10    {Find first window and loop through all subsequent windows in the master window 
11  list}
12    while hWndTemp <> 0 do
13    begin
14      {Retrieve caption text from current window}
15      iLenText := GetWindowText(hWndTemp, cTitletemp, 255);
16      sTitleTemp := cTitletemp;
17      sTitleTemp := UpperCase(copy(sTitleTemp, 1, iLenText));
18      {Clean up the return string, preparing for case insensitive comparison. 
19  		Use appropriate method to determine if the current window's caption either
20  	  starts with or contains passed string}
21      partialTitle := UpperCase(partialTitle);
22      if pos(partialTitle, sTitleTemp) <> 0 then
23        break;
24      {Get next window in master window list and continue}
25      hWndTemp := GetWindow(hWndTemp, GW_HWNDNEXT);
26    end;
27    result := hWndTemp;
28  end;


Once you have the handle you then send the window a WM_CLOSE or WM_QUIT message.
For example:

29  var
30    theHandle: THandle;
31  begin
32    theHandle := HWndGet('Apps Title');
33    if theHandle <> 0 then
34      SendMessage(theHandle, WM_CLOSE, 0, 0);
35    { or SendMessage(theHandle, WM_QUIT, 0, 0); }
36  end;