I have a Dimension4300. It works fine for 3 years. Recenly I upgraded it. I got a second harddrive. i installed Redhat on the second harddrive  and set it as slave, while I keep the winXP on the original harddrive and set it as master. However, I can only boot from the first harddrive and the second harddrive even didn't show up on the boot manual. After boot up from the winXP, there only shows the original drive(c:) too. But if I go to the BIOS, I can see there are two drives: Primary drive 0 and Primary drive 1, and both of them am enabled and with the correct sizes. How can I boot from the second harddrive?