Originally Posted by sb73542
it would be past the 1024th cylinder.
Older bootloaders and BIOS had these problems. You will get good idea about large disks at http://tldp.org/HOWTO/Large-Disk-HOWTO-5.html
Just boot into Linux and the KDE or GNOME desktop should give you good GUI interface to install bootloader in it's control center/system/tools menu (Probably you will find more than one tool to install boot loader) both in Red Hat and in Mandriva. You won't loose any data on installing boot loader. Be careful not to install boot loader into 'mbr' or 'windows' partition.
There is another option [probably best for your current problem]to use external bootloader like XOSL. XOSL is free and can be easily configured to boot any operating system. It is hassle free too. Just install the XOSL bootloader in DOS mode on fat32(win98) partition and specify not to use entire partition for XOSL.
I have no idea how a /boot partition can be defined and used after Linux has been installed. If that can be done I doubt it to be any easier.
fdisk /mbr will always work with any problem with bootloader.