how to specify a file save path to a save macro

I have a working macro which save to documents folder, I have tryed without success to modify this to save to a desktop folder or even a "C:\" drive folder.

working VBA Code

Sub CreatePDFsheet()

Dim FileName As String

FileName = Range("DriverName") & " " & " 29th September 2013"


Range("A4:Q62").ExportAsFixedFormat Type:=xlTypePDF, FileName:=FileName & ".pdf"


End Sub

Failing code

Sub CreatePDFsheet()

Dim FileName As String

FileName = "C:\" & Range("DriverName") & " " & " 29th September 2013"


Range("A4:Q62").ExportAsFixedFormat Type:=xlTypePDF, FileName:=FileName & ".pdf"


End Sub

Any help please!