Thanks for your suggestion! That really helped me to better understand the problem and the boot process, although my problem still exists.
I tried to locate Mandrake's menu.lst in /boot/grub/ but it does not exist. It appears that Mandrake is using LILO as the contents of /etc/lilo.conf would suggest. Now, I'm not sure if it installed the bootloader on the MBR or the boot partition I assigned it. How can I find out what's on the MBR? I would like GRUB (installed with FC3) to be the primary loader for my boot ups and get rid of LILO.
I tried reinstalling Mandrake, formatting the boot and root partitions I designated for it, and installed GRUB as the boot loader onto the Mandrake boot partition, and made sure that the configuration selected GRUB as the bootloader. (I originally choose "skip" to the bootloader installation because I wanted to use FC3's GRUB already in place... so I thought...
) I then tried to find /boot/grub/menu.lst, and it still wasn't there, so I suspect it's still booting from LILO.
Thanks again for your help and look forward to some more!