How do I get my computer to detect all hard drives plugged in?

Just becasue the BIOS detects it, does not mean that XP will.
A couple questions to isolate:
Have you tried that same drive in another computer or configured as the primary Master or Slave?
It could also be a hardware compatibility issue. Have your checked the drive against the HAL for XP?

All the hard drives work, and in computer management the second IDE controller is there.

XP can be a bitch that way sometimes. Even when the BIOS and a live Linux distro can find a drive, XP might not. I think it is a boot block thing; I had a drive that XP detected just fine until I hit it with GParted. Sadly, I cannot remember the exact solution right now as it is close to my bedtime and my brain is fuzzy

Is the disk visable in Windows disk management? Has it been prepared for use?

If its a brand new, never been used before, drive then windows will totally ignore it until it’s been made ready and formated.

It’s old, but I reformatted and it still didn’t show

Reformatting won’t help here. We are talking FIXBOOT and/or FIXMBR here…. unless…

There is a remote chance that it is trying to give it a drive letter that is already in use. There is also the possibility that it has the physical partition but not the logical partition.

Man, I need to wake up. I know I know this, but it’s just not coming back to me :(

@jerv the drive was a secondary just yesterday, now I want it as a secondary slave, so i know it works.

I hope you van remember how to fix this, I want to set the computer up as my personal file server in a manner of speaking.

Also, the taken drive letters are c and f and I tried with 2 hard drives and no dice. I tried with a cd drive and it was detected but not the hd

Is there a logical partition on the drive? I know that messing with the partition table can do odd things and that WinXP cannot handle “illogical” drives the way Linux and the BIOS can.

Was it FDISK that I used to fix it?

Got it! I threw in PM and checked, the drive had no partition table, so I added one, formatted and now it works!

Yay!