Not that hard to find out; just either be brave and open it up WHILE IT'S TURNED OFF, or check the manufacturer's specifications of your computer to find out.
lol. if ur on computer forums you should probably know this by now.
im assuming that if you dont know how much ram u have u probably shouldnt open ur comp. so go to cp then perf and maitence and click system and it should pop up in a window wiht all the info u need.