I have a very old machine running Linux (Fedora 12) with 2 harddrives and a DVD RW. I also have a newer Dell computer running XP. I would like to take the 2 harddrives and DVD RW from the older machine and put them into the available slots in the Dell computer and configure it for dual booting.

How may I do this without loosing everything?

Thanks.

(1) Plug everything in. Hopefully you have enough IDE/SATA slots to fit five drives.
(2) Configure BIOS to boot from your desired master drive, if needed
(3) Boot Fedora live CD. Mount Linux root drive (fdisk -l; mount /dev/sdXY /mnt) and chroot in (chroot /mnt bash). Reinstall grub to the MBR (Google for how for your distro). It "should" pick up Windows and Linux automatically. Then grub will give you the choice.

Have your XP CD around in case you need to repair the Windows bootloader. Installing grub will have to be the last step though.

If the newer system is new enough and you have some extra ram then, I'd consider a virtual machine. Either a P2V app or I simply use dd to an image sometimes.

Then run your old stuff when you want to in a Virtual Machine.