The issue: http://www.48bitlba.com/index.htm
The solution: http://www.48bitlba.com/issues.htm (click on your operating system)
What operating system is on each computer?
What is the model name of the HD?
If you need to update your BIOS and Drivers, go to your motherboard's website or the computer mfg's website.
Even if you can't update the BIOS on the old computer's motherboard, you should be able to install a compatible HD controller card.
I bought a 200gb Seagate Baracuda HDD yeaterday
I have aPC with mercury PIII mB and a P IV with Intel desktop Board D915GLVG
Both do not detect it