Go into the system BIOS or SATA controller BIOS and set the controller to Non-RAID mode. If your controller is integrated in the mobo's chipset (and maybe even if it's in a separate ship), you should then be able to partition and format it. DOS can't see a drive that is not partitioned and formatted, but the partitioning program (FDISK) should see the drive as long as it's in non-RAID mode. And remember that DOS generally can't handle large drives. Try booting from a Knoppix live CD or the Ultimate Boot CD for DOS - those have tools for partitioning large drives. But still if you plan to boot into RAW DOS, you will still need to make 32GB or smaller FAT-32 partitions or logical drives as generally DOS can't see larger. Though a utility is available that will let DOS see large NTFS partitions. Most drive mfr's also have partitioning software you can download from their web sites.
.bh.