you can try 0&0 software's OO defrag , i think you can get an evaluation version from their site (can't remember the name) but you will find it if you search for it.
Actully it is a fully functional version only the sheduler is disabled.
There are other defrags for NT like diskkeeper and I think one from norton too.
But anyway if you have partitions on your disk or even two disks you can always manually defragment then by moving the files from one disk and then getting them back (except for the winnt and some dirs in Program files) wich is by the the fastest way to defragment disks anyway)