I'm not sure you need registered, Nick. I have registered but only because my mobo requires it (practically speaking, anyway). Since PC2700 isn't a
real, bonified standard (AFAIK) I don't think you will be able to find DDR PC2700 anyway. At least I didn't see any on price watch.
Can you run your RAM at a slower speed with some settings in the BIOS on that machine or just lower your FSB to see if that fixes your stabiility problem? You may be underclocking for a while but at least you will be able to trouble shoot that way.
I'm not sure of your system...is it supposed to use PC2700 or PC3200 or what? Can you run your PC2700 at PC2100 (266 mhz) speed just to check if your memory can't handle the higher speed?
If it does turn out to be bad ran, I'd just buy your next stick at Mushkin to be safe...those guys are great over there.
http://www.mushkin.com/cgi-bin/Mush...3e03be62ea273fc0a80102061d+EN/products/990866
C