Cannot insert data into my database

Hello, what wrong with the coding~

Dim myConnection As SqlConnection
Dim myCommand As SqlCommand
Dim ra As Integer
myConnection = New SqlConnection("server=SHAYFEN-PC;uid=sa;pwd;database=shayfen")
myConnection.Open()
myCommand = New SqlCommand("Update User set user_register_login = 'sa'", myConnection)
ra = myCommand.ExecuteNonQuery()
'MessageBox.Show("New Row Inserted" & ra)
myConnection.Close()