RAM is not a magic ingredient that you just increase and it makes things better...
Sure, it improves the overall response of your computer and allows for more softwares to be loaded and running at the same time, or it allows softwares with high memory requirements (such as games) to run better, but only ever so slightly.
CPU, GPU and VRAM are the first things you look at, and even 512 MB is barely enough for DS1.
State your full system specs, as bystander suggested; that means manufacturer, model, working frequency (at least) of any component in your system.
Easiest way to get most of these would be a software called Speccy. It won't provide a perfectly accurate report, but it's usually a nice starting point. For the power supply you...