Purchased a new machine which came with ubuntu linux .... Now I want to remove ubunta linux entirely and load Oracle Enterprise Linux (OEL) which I believe is Red Hat Linux. When I boot up with the Oracle Enterprise CD from the CDROM, it asked me to Select Device Driver.
1) Can the Dell Inspiron 530 run Red Hat or Oracle Enterprise Rel 5?
2) What is the name of the device driver that Red Hat or OEL need to run successfully?
3) Does this device driver run on Inspiron 530?
4) Where can I get this driver (ie. one the web (url?))

If the machine is preloaded with Ubuntu then its hardware is compatible with linux, but maybe you'll need a newer kernel, since the latest version of Red Hat uses 2.6.18 which is somewhat obsolete for newer hardwaers.

Which hardware needs driver?

The Inspiron 530 run RHEL5 and derivatives fine, with one problem:
The normal load order of the ata_piix and USB drivers causes a race condition; this is also tru for normal Ubuntu, but Dell has fixed this by changing the way they load the modules.
For RHEl5 (and probably also Fedora)
1- In the BIOS under "Integrated Peripherals" set "SATA Mode" to "RAID".
2- Install Linux; you will not be able to boot into VISTA
3- After install, in linux as root make a new ramdisk with the ata_piix loaded before USB (mkinitrd --preload=ata_piix --image-version /boot/initrd <kernel version>)
4- Reset the bios to use IDE rather than raid.
You can skip steps 3 and 4 if you only wnat to run Linux.
Niels