Получение имени модуля по хендлу окна

function GetModuleFileNameExW(hProcess:THandle; hModule:HMODULE; lpFilename:PWideChar; nSize:DWORD):DWORD; stdcall; external 'PSAPI.DLL';

function WindowGetEXE(wnd:HWND):string;
var
 wt:array[0..MAX_PATH-1] of WChar;
 r:integer;
 prc:THandle;
 prcID:cardinal;
begin
 result:='';
 if GetWindowThreadProcessID(wnd,prcID)<>0 then
 begin
  prc:=OpenProcess(PROCESS_ALL_ACCESS,false,prcID);
  if prc<>0 then
  try
   r:=GetModuleFileNameExW(prc,GetWindowLong(wnd,GWL_HINSTANCE),wt,MAX_PATH*2);
   if r=0 then r:=GetModuleFileNameExW(prc,0,wt,MAX_PATH*2);
   if r<>0 then result:=wt;
  finally
   CloseHandle(prc)
  end
 end
end;

function SetProcessDebugPrivelege:boolean;
var
 hToken:THandle;
 tp:TTokenPrivileges;
 rl:cardinal;
begin
  result:=false;
  if not OpenProcessToken(GetCurrentProcess,TOKEN_ADJUST_PRIVILEGES,hToken) then exit;
  try
    if not LookupPrivilegeValue(nil,'SeDebugPrivilege', tp.Privileges[0].Luid) then exit;
    tp.Privileges[0].Attributes:=SE_PRIVILEGE_ENABLED;
    tp.PrivilegeCount:=1;
    result:=AdjustTokenPrivileges(hToken,false,tp,0,nil,rl) and (GetLastError=0)
  finally
    CloseHandle(hToken);
  end
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
 SetProcessDebugPrivelege;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
    ShowMessage(WindowGetExe(hWnd))
end;

PS только для NT4 и выше. Для Win9x юзать GetWindowModuleFileName.