Alright, so first of all, I know nothing about computers so please talk to me in a language I understand.
Ok, so on my computer, shaders works terribly slow, a lot of games are slow or super slow, and I want to upgrade my computer.
I have a 2GB RAM, apparently, and my graphics card is NVIDIA GeForce 7050 / NVIDIA nForce 610i.

What do I need to upgrade to be able to play good games with no lag and have shaders with no lag?