My notebook is acting. Actually, it's a loaner. I installed GNU/Linux Debian. It still has its default MS Windows, though. Anyway ... it is acting up, hangs, unpredictable. Sometime it would stay up for more than 1 hour, 2 hours, or more, but other time it would hang in 15 minutes. I suspect it has a problem with RAM. Now, how do I test it (to make sure that it is a hardware problem, not a software / OS problem)? Any suggestion? Is there a Linux program that can (stress) test the hardware (mostly RAM)? Now, I took one of the RAM chips (which I suspect is faulty) and keep it running under Debian. It has been up for more than 1 hour.