To wait for Notepad to finish you need to remember to call the waitforexit method of the process you started. You can also set window size etc using System.Diagnostics.ProcessStartInfo.

 '   
    ' Start a new process (Notepad).
    '
    Dim myProcess As Process = System.Diagnostics.Process.Start("MyTextFile.txt")
    '
    ' Wait until it ends.
    '
    myProcess.WaitForExit()
    
    MessageBox.Show("Notepad ended: " & myProcess.ExitTime & "." & _
        System.Environment.NewLine & "Exit Code: " & myProcess.ExitCode)
    '
    ' Close the process to free resources.
    '
    myProcess.Close()