Lex
Did you buy the Total sticks of Ram together ?. - I may be that both are faulty and even though you have taken one out the other may be giving you problems. Is the type of memory different and is it the right spec and type for your motherboard?. the best thing to try is when you get your new stick put that solely in the machine to test. Also try different memory slots
My PC was crashing due to memory read failures too - after taking all the sticks out, putting them back in one by one in different places only solved the problem.