Check If Files Exist and Return

Hi,
I have been searching here and on the www. for the this but no succes.

I would like to check/search if (FileName As String) is still exists in its directory.
--Why as string: because I have a hidden kollom where the links to the files are in txt format.--

I can't write VBA But maybe I can sketch it?

NOT A CODE

Function CheckFileExistance (Filename as string)
If  Link or Filename as string =  TRUE then
    CheckFileExistance = "File" or "YES" or "A"
Else
    CheckFileExistance = "NoFile" or "NO" or "N.A"
End If
End Function

(MOD: tags even for psuedo-code please... yes, we're that pedantic!)