Here i have tested code u can refer this
Private Sub txtUser_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles txtUser.KeyDown
If e.KeyCode = Keys.Enter Then
after entering the value to Username textbox as soon the user press ENTER , it will focus to Password textbox.
There is a difference between keyPress and keyDown event
The KeyPress event is not raised by noncharacter keys; however, the noncharacter keys do raise the KeyDown and KeyUp events.
U can also use KeyUp
event as SA suggested.
Hope it helps.