Ah, bummer. One thing you might try before you spend any money, this seems to be the case in more than one thread on this forum This is stolen from Kahlil's post, but I wrote it, and I'm quoting myself
Well it may be your ram then if that's the case. Can you adjust timings on your ram from the bios? Try running the fsb at 200, and the ram at 166 and see what happens. Maybe the timings are too tight for that valueram to keep up at 200. If everything works fine at pc2700, you have found your problem, and play with raising the timings to say 3-5-5-10 or something ridiciulously high like that, and gradually bring them back down.