I have been using this company, Data Memory Systems, for over 10 years. Excellent product I have never had a problem with any memory. They're a small company and they stand behind their product.
Not that this is necessarily accurate, but I think on TigerDirect it notes 2 gb RAM - 0 Slots Free. So you'd have to pull out the 2 x 1 gb and put 2 x 2 gb DIMMs in. As far as I can tell you can't buy a 2 gb DDR2 SODIMM yet.
I have been searching for a laptop (essentially a gaming laptop) that I need for 3D graphics. My biggest gripe so far is that no models from brand name companies have larger screen resolutions. Pretty much any wide display notebook with...