You may have bad memory, not a Doze failure of the usual incomprehensible kind. Trouble is (as in a case recently experienced) - if the failure is above the 640K of base memory (I think) -- even though initial memtest may stop counting before max size is reached:

Doze may recognize it all anyway. Or in your case, maybe Doze won't! But you need to find out what is tested at boot-up before even DOS loads, and whether than number is anytime *less* than the max value.

You may have actual memory failure, not a 'leak'; depends on *when* you are looking at memory size -- at boot or, only after Win starts.

Do you mean: while DOS is starting and you see the BIOS info passing by and memory test: you sometimes see *less* than your installed memory?

(If your BIOS has a 'silent boot' feature and it is turned ON: you won't see this early bookkeeping stuff)

If you are now regularly checking only Windows' version of how much memory you have, and sometimes - immediately after Windows starts - you see less RAM: I think I'd reboot a few times and see if you can catch a lower reading on the memtest which occurs before DOS is loaded.

In a notebook, recently - the initial memtest indeed showed "40" MB for what should have been 80. In this case though, Windows recognized the full 80. What the memtest was *really* reflecting was: a 'stuck-bit' at a particular address. This was proven by diags. New memory fixed all the BSOD and other symptoms.

It may be worth your while to observe a series of boots, looking only at the turn- on memtest. Hit f-8 to avoid waiting for Doze to load, so you can test again. If you see a similar symptom to above: power down, remove mem and clean edges with 97% (ie conc.) Isopropyl alcohol and reinsert. Obey static-electricity drill, natch.

That might cure it, but you'd have to again try several boots. It's clear that Windows will recognize memory which the memtest has 'rejected'. (Bad memory in bottom 640K should.. halt the boot, freeze display - at least for some kinds of failure)

PS re the query above, about WHEN all this started: could it have been just after you bought more memory ?? If so, well.. time to run diagnostics on your motherboard and make it "loop" for continual memory test. That would be better than the above tool-free tests.

Diags? - Can't hurt when you have an inexplicable phenom, either all the time or intermittently. Letting Diags test everything and then run overnight, repeatedly checking memory:

As to "base 640K":

DOS is a crude theft of the CP/M OS, slightly redone for a particular microprocessor - as usual with virtually every M/Soft "innovation": stolen from someone who really did know how to innovate, a place called Digital Research.

Without going into details: "640K" in those days was thought to be vastly more memory than anyone would ever need! It became necessary to do lots of clever coding things to address memory beyond 1 MB and then ---> onwards.

IF.. there's a problem in memory within that first 640 Kilobytes (of your 256 or whatever Megabytes of total RAM) - usually the so-called POST (Power On Self Test) will stop everything, with beeps or maybe even a "bad memory" display - depending on exact address of first bad location, regarding the video display.

This would happen while still in the "black screen = DOS" first stage you always pass through before 'Doze loads all its toys.

Anyway.. running Diagnostics may reveal that the new memory IS bad (too) or improperly 'seated' or that the motherboard has suffered "infant mortality failure" etc. Electronics can fail any old time.. no matter what probability says! There's no reason Not to run Diags, so - why not run them?

PS: What I meant about "total memory detected by Windoze" was:

MyComputer/ControlPanel/System [Performance Tab] should show (at least in the 9.x series, dunno re Ex-Pee): what Doze thinks is the total "System RAM". almost always it will agree with POST results -- except in the case I described. Not your problem, here - apparently. Doesn't mean you don't have some subtle memory problem though; just less likely to be It.