|Is the new pc sata? or ide?|
under disk management have you clicked rescan disks?
( xp requires a sata driver if its only ide.)
look in Control Panel, System, Device Manager.
If you have an "unrecognized device"
click on the "Remove" button, & reboot
let Xp find a new drive via the 'Found New Hardware Wizard' appearing after Xp starts. In the opening screen, choose Install the software automatically.
if it doesnt find the required software click 'back', check your motherboard driver disk or download the relevant sata driver,
and point the wizard in the direction of the sata driver.
The disk management usually is only required for unformatted disks, formating partitioning etc,
try another sata cable, as a last resort,
post your pc motherboard spec if still no joy.