I read your other post and thread. If disabling the raid contgroller in the bios doesn't help, I would get my hands on a floppy drive and install it. Get a windows 98 se boot disk and try to boot from it. If successful, choose to start the computer with cd rom support, you can then (fdisk) delete and repartition the drive. Also you can type in SYS C:. This will cause the bios to recognize the drive as a system disk.
Then change the boot order (in bios) to boot from cd rom first. At the A:\ prompt, type D: then enter. When the prompt changes to D:\, Place the xp cd in the drive and type Setup then enter. I've done this successfully before when I couldn't boot from the hdd.
You may get a message that says there is no drive installed, but keep trying.
You may have to try the setup command numerous times, but eventually the cd will boot. You can then format and install the os.
I won't guarantee that this will work for you, but it has worked for me, more times than one.
Best of Luck.
Here is my dilemma. I build a new computer buying a case, motherboard, cpu, and cd burner. For budget reasons I am using my old hard drive (Western Digital 80 gig). The hard drive is recognized by the bios. When I boot windows from the CD (windows xp) and it gives me the option to repair or install windows and I make my selection I cannot precede any further because it says windows can?t find a hard drive. Once again my hard drive is seen in the bios. I have checked and rechecked my cables and jumper settings and nothing is amiss. Help!!