I have the referenced Sony notebook and when I try to install an additional RAM module, it is not recognized. Someone says you can use something like a folded up post-it note under the module panel to exert extra force on the module. I tried that to no avail. Does anyone have any other ideas? I understand this might be a fairly common Sony problem.
I remember a problem that plagued Sony notebooks from a year or two ago, and finding another forum somewhere that had detailed info and many posts on the problem. I'd suggest typing your Sony model number and the words ram and memory into Google. It will take you a little time to plough through the hits, but you might get to a site like the one I mentioned.