There is a File System Object
that does more than a file exist (check the msdn)
1st
add a reference to scrrun.dll from the wintnt/system dir
2nd create the object
private objFileSystemObject As Scripting.FileSystemObject
Set objFileSystemObject = New Scripting.FileSystemObject
Finnaly used it in you apps
eg if objFileSystemObject.FileExists("c:\autoexec.bat") then
....

do not forget to set objFileSystemObject to nothing

PS
with this object you can create, delete folders and files
and also create txt files and write or read from txt