i'm guessing that you have an older pc, thus an older bios.
the bios is not able to detect hd's greater than 30 gb it seems.
there is a solution though. your hd should've come with a boot cd/floppy that contains software to allow your bios to recognize the full drive.
maxtor has the maxblast software that does this.
check out this link - >
http://members.shaw.ca/rinocanada/hdutils.htm it has a link to a proggy that might be able to do it for samsung drives.