salami1212,
first off, could you plz provide a lil more info?
like, what type of memory are u using/amount ?
mobo?
and how many sticks do you have installed right now?
do u know how to take out your memory sticks?
if you do, and you have..say, 2 sticks in..then try to take 1 stick out..and test a game to see if it crashes..repeat w/ the other stick.
of course doing Memtest86 would help, but doin it the way i mentioned would too.
let us know how it goes.