External hardDisk not recognised

[KSegg]

I have a Segate 50GB external harddisk which is not recognised by my comp.
Comp configuration: AMD 2.0 processor, 512 RAM, ASUS motherboard, USB 1.1
I have seen it doesnt works with AMD machines but with Intel machines the harddisk works fine.
Is it the problem with processor or the external casing or the harddisk?

1. Version of XP - XP Professional SP2
2. Hardware setup - Segate Harddisk
3. What exactly happened leading up to the problem - No Idea
4. Exact error messages - No message shown as the disk is not even identified
5. Any antivirus, firewall software you are running - Windows default

If i connect my Mobile phone with USB cable to comp it works fine without problems, so no problems can be there with the USB ports.

Any Solutions??