Hi Miguel, A comprehensive memory test requires a diagnostic utility. Non-fatal memory errors can get through HIMEM.SYS and still be the cause of GPF or illegal operation errors without the blue screen of death stuff, but usually, a thoroughly trashed memory SIMM will be detected by HIMEM.SYS during the boot-up to Win95 or DOS 7. Finding the bad chip after that can be done by simple process of elimination, taking them out one at a time until the error message stops. As for the memory count, even if you enable CMOS for the better test, (or disable the quick power-on test) it is pretty worthless in my opinion. Tom Turak [log in to unmask] Is the "memory count" during the power-on-self-test (POST) enough to determine if your RAM chips are good??? Or, do you need a special diagnostic utility to detect defective RAM chips. Thanks in advance! Miguel Morillo [log in to unmask]