handling spaces in file names

I am using VBScript to write some system management
scripts on XP.

I am having problems when a full path filename contains
spaces:

e.g. I define a constant string as
Const defragcmd = "C:\Program Files\Norton
SystemWorks\Speed Disk\sdntc.exe"

Then try to run it using WSH:
Dim WshShell
Set WshShell = WScript.CreateObject("WScript.Shell")
WshShell.Run defragcmd , 1, true

This fails as script reports can not find specified file.

I get the same error with

WshShell.Run """defragcmd""" , 1, true

How can I pass the filename containing spaces to WSH?

What I am trying to do is run the defragcmd on several
disks so the first part of the cmd is the constant then I
want to add the options before calling WSH e.g.

cmd =defragcmd & " -drive=" & osdisk & " -auto"

But I am stuck with that space in the full path name. Any
ways round this?

Thanks

David