Scott:
There are two basic requirements for Windows XP to recognize the full
capacity of large-capacity drives, i.e., drives having a capacity greater
than 137 GB.
1. Your mainboard's BIOS must support large-capacity disks, and,
2. SP1 or SP2 has been installed at the time the drive has been installed.
Contact HP to see if your motherboard's BIOS supports large-capacity disks
and if it doesn't, whether any BIOS update is available to provide this
support. Ensure that SP1 and/or SP2 has been installed on your system before
you install the new HD.
In the event your motherboard does not support large-drive capability, you
can purchase a controller card such as the Promise ULTRA133 TX2 to support
this capability. They're not terribly expensive, running about $35.
Art