Skype Profile Image Downloader in Visual Basic

Private Sub skypeButton_Click(sender As Object, e As EventArgs) Handles skypeButton.Click
	Dim username As String = skypeText.Text
	Dim runDownload As Boolean = True
	If (username.Length >= 6 And username.Length <= 32) Then
		'Next code goes in here.
	Else : MsgBox("Username is not the right length!")
	End If
End Sub

Dim allowed As Char() = "abcdefghijklmnopqrstuvwxyz0123456789"
	username = username.ToLower() 'Easier to check against the allowed characters, case insensitive.
	For Each character As String In username
	Dim isFound As Boolean = False
	For Each c As Char In allowed
	If c = character Then isFound = True
	Next
	If Not (isFound) Then
		MsgBox(character)
		runDownload = False
	End If
Next

If (runDownload) Then
	Dim link As String = "http://api.skype.com/users/" + username + "/profile/avatar"
	Dim fs As New SaveFileDialog
	fs.Filter = "JPEG Files | .jpg | PNG Files | *.png"
	fs.FilterIndex = 1
	fs.ShowDialog()
	If (My.Computer.FileSystem.FileExists(fs.FileName)) Then
		Dim result As MsgBoxResult = MsgBox("File already exists, overwrite it?", MsgBoxStyle.YesNo, "File Exists")
		If (result = MsgBoxResult.Yes) Then
			Dim wc As New WebClient
			wc.DownloadFile(link, fs.FileName)
		End If
	Else
		Dim wc As New WebClient
		wc.DownloadFile(link, fs.FileName)
	End If
Else : MsgBox("Not all the characters meet the Skype requirements for a username. Please try again with a different username")
End If