The other day my friend and I were going to upgrade his computer by adding more RAM. We took out the old RAM and figured out it was a (256MB) 184pin stick, meaning it is DDR SDRAM, correct? We figured that out by looking at a PC hardware book and the stick looked exactly alike the DDR SDRAM pictured (one little gap where the pins are, and 2 gaps on each side). Except this stick was only one sided, it only had the chips on one side.

So after purchasing a new DDR SDRAM (256) stick (2 sided), it goes in perfectly. So then we boot up the PC and the BIOS makes some beeping noises (indicative that it rejected the RAM, I forgot how many times it beeped). The PC doesnt boot up, not even to the BIOS or anything. So we try a few more times, switching slot places, one chip at a time and on and on and it doesnt take the new double sided RAM.

So my question is, why doesnt a one sided DDR SDRAM stick work with a 2 sided one? Or are they supposed too... if they are I guess that new stick wasnt any good??