This is normal on a Dell server. You’ll need to go to Dell’s website and download the Perc drivers for that model of server. These are the drivers for the SCSI/RAID card that Dell uses. The drivers aren’t included in Windows CD/DVDs. You’ll need to put the drivers on a floppy disk, and when you boot of the Windows disk press F6 or F8 at the very beginning so that you can install the drivers. If you watch the bottom line of the screen it’ll tell you what key to press.
If you don’t have a floppy drive you’ll need to go and buy a USB floppy drive and the drives can only be installed off of a floppy disk.