OEM XP w/SP2 Bluescreen during new install

Greetings, all.

PMFJIH, but I've got a situation which has me stumped, and googling
for it hasn't helped.

The situation is this: Two identical systems, neither of which will
install OEM XP w/SP2; after formatting the drive and copying the
files, it bluescreens during the hardware detection phase with a stop
0xD1 and the infamous "IRQL_NOT_LESS_OR_EQUAL" error. I've changed
video, memory, even processors, all to no avail. I've tried changing
CPU settings in the bios; I've flashed to an earlier bios version.
We've even gone out and gotten a different copy of XP from another
vendor.

Here's the kicker, however -- earlier versions of the OS load just
fine, and have no issues with loading SP2 separately later. Only the
current discs with SP2 seem to have this problem.

System specs:

Asus P5P800 motherboard with 1011 bios (latest), 865PE chipset
Intel 3.0GHz 630 processor, LGA775, 2MB L2 cache, 04A stepping
Kingston ValueRam KVR400x64C3A/512 memory module
Asus V9400-X video card, Nvidia MX4000 chipset
Western Digital 80GB SATA hard drive

If anyone could possibly hand me a clue-pon or three, I (and the
customer who is purchasing these systems) would greatly appreciate it.