Preguntar si existe el proceso

Public Declare Auto Function FindWindowNullClassName Lib "User32.dll" Alias "FindWindow" (ByVal lpClassname As Integer, ByVal lpWindownName As String) As Integer

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        Dim hWnd As Integer = FindWindowNullClassName(0, "Administrador de tareas")

        If hWnd = 0 Then
            MsgBox("no hola")
        Else
            MsgBox("hola")
        End If
    End Sub