First get the exact mfg (SONY), series (VAIO) and model # (??????).

Second check the system manual for info on RAM and CPU upgrades. need to check on the installed RAM....the system shows ???MBs of RAM using 1 DIMM or 2 DIMMs ???

Then go to and select mfg, series and model number's usually very good about telling you how many RAM slots there are, the max RAM and what type of RAM it takes...DDR, DDR2, etc. and offers you some RAM options...guaranteed to work with your system.