The way your code is now only the last folder is used, with each
statement you are overwriting the previous value. So in effect only the files in the folder from the statement
Set objFolder = objFSO.GetFolder("C:\Documents and Settings\" & objnet.UserName & "\Belgelerim\mailbox")
In order to look in all the folders execute the file searching code
For Each objFile in objFolder
If LCase(objFSO.GetExtensionName(objFile.Name)) = "pst" Then
Note: Instead of repeating the code several times you should place it in a separate procedure.