Memory Gone Bad

So I've been having lots of computer problems lately. But the latest keeps my computer from booting; my memory's gone bad. I tried reseating it, taking different sticks out, everything. Apparently it's all gone bad. I went and bought some real RAM this time (as opposed to last time where I didn't much care for quality). Anyway, my question is, does anyone know how memory goes bad? I don't want to fuck up 60 dollars worth of new RAM right off the bat because I don't know what I am doing.

possible the last memory overheated and fried the ships. or if there was alot of dust that dust could have caused a static charge which fried the chips as well.