>I'm sorry...I changed the forum to write this question and my message was sent here anyway !!!
>
>If somebody could answer anyway, I'll appreciate
>
>Tanks again
>
>Benoit Grenier


Either the memory is going bad, which is why it doesn't happen all the time, or it is DRAM and it has come slightly unseated (through heat expansion and contraction, etc)from the motherboard. (Or it is just bad memory.) Anyway, as a general rule, anytime a system boots up fine sometimes and sometimes not, it is usually a memory problem.