Go to Crucial.com and do a system scan, any memory bought from them is guaranteed to work with your system, my esprimo mobile 5505 takes up to 4gb when scanned by them.

I have an Esprimo Mobile 5505 notebook running Vista Home premium, I have been unable to receive any automatic updates for a while and am unable to install SP1 for Vista, I think this has been the cause of a few problems I've been having such as an 8gb USB stick not showing (works fine on my mac and...