Download Button - File Downloading Cancels Other Operations

In my project, I've created a download button. This button shall perform 3tasks:

1. Change label text
2. Download file
3. Make the button invisible

The following code changes the label text and make the button invisible:

Code:

Protected Sub btnDownload_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnDownload.Click
lblDownload.Text = "<h3>Thank you for downloading </h3>"
btnDownload.Visible = False
End Sub

When I add a piece of code that handles the file download, the label text is not changed and button remains visible.
Here is the code:

Code:
Protected Sub btnDownload_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnDownload.Click
Dim URL As String = "~/myfile.exe"
Dim fileInfo As FileInfo = New FileInfo(Server.MapPath(URL))
If fileInfo.Exists Then
Response.Clear()

[Code] ....

File downloading cancels other operations.