|Test drive in known working machine. |
Swap controllers IDE0 to IDE1.
See also jumpers on HD. Be sure you understand all options.
Swap IDE cables,. be sure you are using only the best quality.
After all that, XP may not even need to have it be "seen" in bios to work.
"Best Practices", Event viewer, host file, perfmon, antivirus, anti-spyware, Live CD's, backups, are in my top 10