Here is the already BLOCKED PID Range in Windows XP/Home SP2.
XXXXX-640-0000356-23XXX
XXXXX-640-2001765-23XXX
XXXXX-640-643718x-23XXX
XXXXX-641-309376x-23XXX
XXXXX-642-064580x-23XXX
XXXXX-642-464364x-23XXX
XXXXX-643-334701x-23XXX
XXXXX-644-081772x-23XXX
XXXXX-644-451265x-23XXX
XXXXX-644-874896x-23XXX
XXXXX-644-933704x-23XXX
XXXXX-644-962396x-23XXX
XXXXX-645-833254x-23XXX
XXXXX-645-994962x-23XXX
XXXXX-646-031843x-23XXX
XXXXX-646-104081x-23XXX
XXXXX-646-105103x-23XXX
XXXXX-647-318838x-23XXX
XXXXX-647-592029x-23XXX
XXXXX-647-677834x-23XXX
XXXXX-648-301691x-23XXX
XXXXX-648-819992x-23XXX
XXXXX-649-106765x-23XXX
XXXXX-649-941392x-23XXX
XXXXX-650-292312x-23XXX
[courtasy of wzor, iexbeta, n1n0r... and beyond?
]