How to know that you have a RAM problem

RAMs problems can't be easily specified because many other hardware problems have the same effect on you PC, but if you have a damaged RAM, you will note that the computer give you a blue screen suddenly and this will occur many times specially if you try to open a big application or game that consumes a large space in RAM.
If you have a copy of Linux operating system on a bootable CD or DVD you may find a memory test program or try to get one from the internet and use it to check your PC's RAM. If you find any errors then try to check each RAM alone if you have more than one,but the faulty one can't be repaired in most cases,so it's recommended to buy RAMs that have a long warranty or a live time warranty like Kingston to make sure that you won't pay more money on such hardware that can be easily damaged by heat.