If all that's on the drive was linux, use the boot and root disks and log in as root. Once you've done that, run linux fdisk. hit p and return and find out what partitions are on the hard drive. Then it's a matter of using deleet command in fdisk which is d, and giving everyone of the partition numbers you read earlier. The partition numbers will be in the first column of the table produced by the p command. Once everything is deleted hit upper-case w to write the disk and that should get you back to the root prompt. At that point, make your decissions as to how you want to partition your disk and go from there. I find fdisk easier to use than cfdisk personally.
