I wish to upgrade the RAM on my computer. I currently have 2x256 DDR (PC2700) 184-Pin DIMM. I was sent by my computer supplier a Crucial 512MB 184-Pin Dimm DDR PC2700 which I duly inserted. The device manager indicated that increased RAM had been detected, however after a short period my computer just shut down for no apparent reason. I removed the original 2x256 RAM and the computer worked fine. My supplier suggested that when adding RAM the slots should all be of the same size i.e. all 256 or 512 not a mixture which from my experience seemed logical, however on visiting the Crucial web site for advice prior to the purchase of the additional RAM they stated that RAM could be mixture providing it was the same make and type i.e. 184-Pin PC2700 etc. Could you advise?