Another question on dual booting (Fedora Core II and XP)

[FENG FENG]

Under Fedora Core Rescure:

run : fdisk -l /dev/hda  
got:  14589, 255, 63 (C,H,S)

then reboot and press "DEL" enter BIOS
get HD info: 14588, 255, 63 (C, H, S)       (LBA mode)

why I got the different geometry info? 
What's the problem possibly?

Many thanks.