Add a Label and a Timer component in your form and set the starting date and time (the date won't be visible). So if you set 17:35:00
the time will start from that moment and be updated every second like a clock.
Public Class Form1
Dim startTime As DateTime
Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
startTime = New DateTime(2014, 1, 1, 17, 35, 0) 'setting time at 17:35:00
Label1.Text = startTime.ToString("HH:mm:ss")
Timer1.Interval = 1000 '1 tick every second
Timer1.Start()
End Sub
Private Sub Timer1_Tick(sender As System.Object, e As System.EventArgs) Handles Timer1.Tick
startTime = startTime.AddSeconds(1)
Label1.Text = startTime.ToString("HH:mm:ss")
End Sub
End Class