Ok---Tracking down what exactly is calling this app could take a while... you have no idea?

I just determined that the symptom I described seems to be unrelated to the subtle ntvdm.exe issue. Because I just copied a bunch of files to a different folder and a number of them ended up corrupted again, without the 16bit VM loader process present. The last reboot is less than 24 hours ago too and the system has been running idle a lot, not much I could have done with it that would have made it unstable that way... :/

Bud... I really would encourage you to run the prework. You have nothing to lose by doing so.
We should really eliminate any possible infections before going further. Files don't just corrupt themselves... especially at idle.
There are viruses and spyware that can hide themselves from "standard" scanners. Something's not right here.

I am going to consult with our security/tech leaders to see what they think.

hello zoid, and welcome to the forums.....first thing I would do is verify the integrity of the file structure using sfc.exe. Instructions at scannow sfc - LEARN how to use SFC.EXE (system file checker) in this article!.

Let us know how that goes, and if you are still experiencing instability issues, we can dig deeper. Next step after that is to check the disk itself.

Thanks,

v

With all due respect folks, but I've been through all that integrity and malware checking already, more than once. I wouldn't ask here if it was that simple, I'm usually extremely aware of what exactly runs on my computers and what connects to it and all that.

Meanwhile, I tried (and tried, and tried... grrr) to reproduce the conditions under which the data corruption occurs, putting the system under various loads, using apps that I commonly and rarely use, a bunch of things. I think I can narrow it down to two candidates. One is visiting a certain website that heavily relies on Java, and if that's the case, a Java update from sun.com should help (my current Java is fairly old). The other candidate, and probably the more plausible one, is Motherboard Monitor (if anyone remembers that, it's been discontinued for a few years already). I was beginning to speculate that this either might be Explorer screwing up when it does File Write operations, or one of my apps installing a device driver that's just not working well. And MBM does have its own driver and is of course fairly hardware-centric too, so that would kinda fit.

Whether it's MBM itself, or MBM in conjunction with other apps that I happen to use, or MBM just on my system, or maybe occurs with any such sort of system monitoring app on my PC under XP, I don't know (yet). But I have a hunch that's the culprit. I'll let you know when I get any wiser.

well, if you've tried sfc, and it cleared, then it's not a file issue. As the rig is new, I doubt it's a driver issue, and it doesn't sound as if you have too much additional hardware on there.

Did you build this yourself, or is it a factory rig?

To answer your question, yes, I have seen this several times before, and in each case it was a virus that was causing it, but you seem to be adamant that that is not the case.

Was this a new hard-drive, and where did the OS's come from? If they (or rather, the xp one) is still under warranty, I'd repair install the OS and go from there. Which is the system os, the 98 or xp? It literally sounds like a zero-fill app running on your machine, but randomly, which is why I think 'virus'. Due to the fact that it's filling exact cluster sizes, and that's what a zero-fill app does (such as dban), I'm rather curious about it.

Do you ever d/l anythnig from p2p sites?

v

I think I figured it out. Hopefully. My initial guess with Java or MBM was wrong, it's always the most casual apps that creep up on you...

This PC has a bt8x8-based tuner card (Pinnacle PCTV Pro). One of the apps I use with it is for listening to FM radio, called "bRadio" (freeware formerly from borgtech.org, now dead and discontinued). It's a nifty little program that works better than any other similar app I've seen, but apparently not on XP, or at least not on my setup. bRadio usually installs one library to \system and one low-level hardware access driver to \system32\drivers, and the latter driver is of course OS-specific (i.e. it's a different driver depending on whether you install it on Win9x or NT/XP).

I can reproduce the symptom I initially described consistently when running bRadio, after tons of testing there seems to be no other condition under which it occurs. My litmus test is copying (thus writing) a large number of JPEG files/photos to a different location, no matter on which of my drives. Browsing the target folder with Irfanview gives me an instant visual overview and verification of the symptom occurring, or not occuring.

Whatever work I do with the PC, no file corruption, everything's fine. I start bRadio, I run the copy test above, usually everything seems to be fine too. When I close bRadio, I run the copy test and get about 20% corrupted files. This is cumulative, i.e. the amount of corrupted files for every copy operation increases whenever I start and close bRadio. So my guess is, the root cause of the problem is trying to unload that hardware access driver upon closing the app.

Why this is the case, and if it's really just that or maybe can happen with other apps as well, and whether it's sloppy/buggy coding on the driver or just a coincidence on my system, just some incompatibility with some other stuff that's unique on mine - I have no idea. But in any case, this seems to be it.

Oh well, hope this helps someone else too. Thanks for your efforts, everyone.