MY HD READS ONLY 2 GIG(on a 10 gig hd)

i recently have done a few setups for 2 pc.i notice that all of my components works beautiful , but on both pc’s i read only 2 gigs and one is a 9 gig and the other is a 10 gig HD’S. i’m running win 98 and is not like nt4.0 that you can keep creating other drives if you have more space.how can i set this to its full drive space?without loosing data