Backup system partition only on 2 partition drive

I have TI 2010 - win xp pro

1 hard drive split into 2 partitions:-

D: contains the operating system

C: contains all the data

When I try 'one click backup' the program selects both C: and D: together to back up.

I don't want to back up the data files, it's not necessary.

How can I force it to backup just the D: with the system on it ??

Any help please.

Daveoh