i would say reset the bios (turn off the computer, then turn the psu off and back on after 15 sec and boot up again), and stress test that. If it doesn't pass then you got a DOA and your going to have to figure out which component it is (although that brand of memory is not very fimiliar so that would be my first guess if it isn't stable at stock...use memtest95 to test it with 5 cycles). Then start over again with the overclock, if the system passes at stock.
Thats about all i can think of now.
CPU: e6600 @ 3.2ghz
RAM: 2GB G.Skill HZ PC6400
Mobo: ASUS P5B Deluxe
GPU: Sapphire HD4870
Soundcard: Creative Labs X-Fi XtremeGamer Fatal1ty
HDDs: 250GB WD + 750GB WD + 2x1TB WD
Monitor: Samsung 226BW
PSU: OCZ GameXStream 600W
Case: Cooler Master Stacker
OS: XP Professional SP3
Mouse/keyboard: Logitech MX518/Saitek Eclipse II
Speakers: Logitech Z-2300