i tried above code, did not bring to front. i modified code, now only opens (1) calculator, and if behind my form, brings to the front. only issue, if calculator is minimized, does not bring up from taskbar??

 Dim calc As Process = Process.GetProcesses.FirstOrDefault(Function(p) p.MainWindowTitle = "Calculator")

Dim r() As Process = Process.GetProcessesByName("CalculatorApp")

If r.Count > 0 Then
    'bring calculator to the front
    BringWindowToTop(calc.MainWindowHandle).Equals(True)

Else
        'open the calculator
        Process.Start("C:\Windows\system32\calc.exe")
End If