Check if file exists?

How can I check if a file exists? Something like

Code:

---

If (file doesn't exit) Then
  Response.Write "Can't find that file"
Else
  ' Proceed to download file
End If

---

If CreateObject("Scripting.FileSystemObject").FileExists(strFileSpec) then

OR if ASP
If Server.CreateObject("Scripting.FileSystemObject").FileExists(strFileSpec) then