Hey all. I've tried being a nice net-citizen. I did a bunch of searches, yes including this forum. I know there have been a LOT of these on here (machine check error blue screens). Read the advice, trying to figure out what I can try next. I am trying to fix a BSOD as a favor. The first time I had been up there I made some minor changes at startup in case it was a software conflict he didn't need to load anyway. I also ran memtest and it came up fine. Couldn't do much more at the time and it seemed to be booting fine, so I left. A few days later he calls and says it started happening again. I brought the system to my place and have been looking at it here. It will now almost never load into XP (where it apparently had been working fine a few days after I went up). So it seems to have somehow gotten worse over time. The now: This thing is so unstable it will almost never get past flashing up the XP loading screen a second or two - lots of times dumps before that. Once I got to the desktop, but before finishing loading it, it dumped. This is the same for both normal and safe mode. So I can not boot this thing. What I've done: Ran Memtest - it's fine. Actually replaced the two sticks with a third stick that's in there now - same BSOD. Swapped in a new PSU - same BSOD. Swapped out the HD to another system. This results NOT in the same BSOD, but the system hangs at a black screen before the windows loading screen comes up. So *no* BSOD, but still a fatal hang with no explanation. This leads me to believe the problem lies somewhere with the HD / or XP data. Wanted to swap in second system's HD to the problem unit to see if it boots fine (which should rule out everything *except* the problem unit's HD if it booted fine) - but I can't figure out how to remove the plastic casings / HD mounting from either Dell system and the PSU and IDE cords are too short to reach otherwise. I hate Dell. I would smash the plastic fronts off to look for more screws, but it's not my system, lol. Yay for doing favors. If you feel the effort is worth it I can spend more time figuring this out, but I feel from the first HD swap that should already be pointing to the HD as the problem. If you feel otherwise, I can do this step to generate more evidence pointing to the HD (if the 2nd HD boots fine in the problem unit). These units are nowhere near the same model, but they're both Dell and both windows (I think one is 98 and one is XP) so I'm not sure what kind of hardware issue(s) (maybe XP doesn't have legacy hardware driver support for something?) might have the problem unit's HD hang in trying to load in the older system. I feel that's less likely though. I am currently running a generic general HD diagnostic on the HD (Seagate test) and will probably run a second one to be sure (probably maxtor) - but completing both of those will likely take another 6-ish hours. My feeling is the HD will pass these tests (it is also not making any strange sounds that I have heard - take that for what you will). Since I can not boot the system, I can not install any temperature-monitoring apps to see on that. I am not a test lab, and have no other way I can think of to do this. Since the BSOD often comes up before even the windows loading screen pops, I'm fairly confident a heat issue is less likely. It had also been running fine for about a year or two (it's a fairly new unit) - and my experience with PSU contact paste to the cooler is that it's pretty much locked on there and isn't just going to pop off one day while sitting on the desk not being moved. My experience is not OEM system construction though, so I have no idea if they use the same kind of attachment method I've been using in my custom builds. The BSOD mentions a Machine Check Error, which should be hardware. Is it possible this is actually a driver issue somewhere and not related to a *hardware* issue? The only thing the owner could remember being installed differently recently was some kind of software to get photos off a USB camera. I had previously uninstalled all "junk" programs I had seen, and removed what I think was this camera software from startup as a precaution. It continued to happen. So is it possible this is a driver issue? If so, can there be ANY WAY to fix it if I can not boot the problem unit without a reinstall? Does a Dell OEM reinstall off their disks lose data, or just overwrite the system files like a generic XP reinstall? I've done generic reinstalls to fix driver issues before (I'm 90% sure, it's been awhile), but I don't want to do that with the Dell disks if there is going to be data loss. My options now look like: - try a reinstall overtop of XP and pray no data gets wiped in the process (or do the next thing and reinstall afterwards) - try to boot it as a slave to another XP / NTFS drive (the 98 machine wouldn't work because it's FAT-based not NTFS, ya?) and back up, then just format it and reinstall (yay). - would a system file checker (SFC) or something else possibly work? I assume this would be driver related if not hardware related, and I'm not sure SFC could do a damn thing about a driver issue, could it? Also, if it was file system related or something SFC COULD fix, I would assume I would get something other than Machine Check Error, right? If there are any other options you could think of, I'd love to hear them please = ) Thanks!!!