Your BIOS is only recognising them as 128Gb drives, so you're not seeing all the space. I'd suggest updating your BIOS and your drivers - if that doesn't work I'm afraid you're stuck (under windows - Linux would see all the space!)
It may be worth checking the back of the drive to see if there's a "128Gb Clip" function on them - I suspect not, but worth checking.
you didn't say if these were PATA or SATA drives
if PATA you might try changing the drive detection in
bios from AUTO to LARGE or try imputting the drive spec's
manually. but most likely a windows proplem ( didn't see what
OS your using.
SATA drives means a proplem and most likely
a bios update to try to solve
Aside from what is already mentioned, if you are installing a version of XP that is not service pack 1 (sp1) or later then the OS can't see it:
How to enable 48-bit Logical Block Addressing support"]Windows XP does not support 48-bit LBA support unless you are running Windows XP SP1. If you want to use 48-bit LBA support, you must apply Windows XP SP1 or later. Windows XP Media Center Edition and Windows XP Tablet PC Edition already include SP1.
Also, if you enter the bios it should tell you what it size drive it is seeing. That will narrow it down to hardware vs software. Personally I would make sure I had the latest bios regardless in addition to SP2, it's good to keep it everything updated.