Search on click

I need help on a function on where you enter lets say a email. It verifies that the email is on a certain website and it lets you login. I already inplemented a generate code but it isnt enough.

Edit: Request close sorry! I found and fixed my own problem!

Dim wc As New WebClient
Dim strings As String
strings = wc.DownloadString("Site")
wc.Dispose()

If strings.Contains(HWID) Then

MessageBox.Show("HWID Matches!", "******", MessageBoxButtons.OK, MessageBoxIcon.Information)
Label4.Text = "Successful Login!"
Me.Visible = False

Form1.Visible = True

Else
MessageBox.Show("Fail login. You are probably not in the database. Post your generated HWID Key!", "******", MessageBoxButtons.OK, MessageBoxIcon.Error)
Label4.Text = "Failed Login!"
End If
Catch
MsgBox("Unexpected error. Please try again!")
End Try

That is a VERY insecure way of doing it.