How to make an updater?

[thefiscster]

Ok, So I am trying to make an updater for one of my applications but i need to know how to figure out if the updated file exists. I have this but it doesnt work... i was wondering if anyone could tell me how to do this. I would be very greatful. Thankyou...

Current Code:

Public Class Form1

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        If My.Computer.FileSystem.FileExists("http://www.domain.com/file.exe") Then
            My.Computer.Network.DownloadFile("http://www.domain.com/file.exe", "C:/file.exe")
            MsgBox("YES")
        Else
            MsgBox("NO!")
        End If
    End Sub
End Class

Thank you for ANY help.