[code]
// function IsModuleLoaded to call at install time
// added also setuponly flag
function IsModuleLoaded(modulename: String ):  Boolean;
external 'IsModuleLoaded@files:psvince.dll stdcall setuponly';

// function IsModuleLoadedU to call at uninstall time
// added also uninstallonly flag
function IsModuleLoadedU(modulename: String ):  Boolean;
external 'IsModuleLoaded@{app}\psvince.dll stdcall uninstallonly' ;

//;判断进程是否存在
function IsAppRunning(const FileName : string): Boolean;
var
    FSWbemLocator: Variant;
    FWMIService   : Variant;
    FWbemObjectSet: Variant;
begin
    Result := false;
    try
      FSWbemLocator := CreateOleObject('WBEMScripting.SWBEMLocator');
      FWMIService := FSWbemLocator.ConnectServer('', 'root\CIMV2', '', '');
      FWbemObjectSet := FWMIService.ExecQuery(Format('SELECT Name FROM Win32_Process Where Name="%s"',[FileName]));
      Result := (FWbemObjectSet.Count > 0);
      FWbemObjectSet := Unassigned;
      FWMIService := Unassigned;
      FSWbemLocator := Unassigned;
    except
      if (IsModuleLoaded(FileName)) then
        begin
          Result := false;
        end
      else
        begin
          Result := true;
        end
      end;
end;

//;通过名称终结进程
procedure TaskKillProcessByName(AppName: String);
var
  WbemLocator : Variant;
  WMIService   : Variant;
  WbemObjectSet: Variant;
  WbemObject   : Variant;
begin;
  WbemLocator := CreateOleObject('WbemScripting.SWbemLocator');
  WMIService := WbemLocator.ConnectServer('localhost', 'root\CIMV2');
  WbemObjectSet := WMIService.ExecQuery('SELECT * FROM Win32_Process Where Name="' + AppName + '"');
  if not VarIsNull(WbemObjectSet) and (WbemObjectSet.Count > 0) then
  begin
    WbemObject := WbemObjectSet.ItemIndex(0);
    if not VarIsNull(WbemObject) then
    begin
      WbemObject.Terminate();
      WbemObject := Unassigned;
    end;
  end;
end;

//;安装的时候判断进程是否存在，存在则先提示是否结束进程
function InitializeSetup(): Boolean;
begin
  Result := true;
  if  IsAppRunning('{#MyAppExeName}') then
  begin
    if MsgBox('安装程序检测到 {#MyAppName} 正在运行！'#13''#13'单击“是”按钮关闭程序并继续安装；'#13''#13'单击“否”按钮退出安装！', mbConfirmation, MB_YESNO) = IDYES then
    begin
      TaskKillProcessByName('{#MyAppExeName}');
      TaskKillProcessByName('{#MyAppExeName}');
      Result:= true;
    end
    else
      Result:= false;
  end;
end;

//;卸载的时候判断进程是否存在，存在则先提示是否结束进程
function InitializeUninstall(): Boolean;
begin
    Result:= true;
    if  IsAppRunning('{#MyAppExeName}') then
    begin
      if MsgBox('卸载程序检测到 {#MyAppName} 正在运行！'#13''#13'单击“是”按钮关闭程序并继续卸载；'#13''#13'单击“否”按钮退出卸载！', mbConfirmation, MB_YESNO) = IDYES then
      begin
        TaskKillProcessByName('{#MyAppExeName}');
        TaskKillProcessByName('{#MyAppExeName}');
        Result:= true;
      end
      else
        Result:= false;
    end;
    // Unload the DLL, otherwise the dll psvince is not deleted
    UnloadDLL(ExpandConstant('{app}\psvince.dll'));
    DelTree(ExpandConstant('{app}'), True, True, True);
end;