You can upgrade it to 4GB (http://www.cnet.com/laptops/acer-aspire-as5734z-4836/4505-3121_7-34150250.html), but assuming that you have a 32bit Windows, that will make no sense, because only 3,5Gb will be seen by windows. Save the money for a new laptop. Even a cheap one will be way faster then your old one.