I'm a veterinary technician, not a computer tech, so I'm out of my depth on this and need help, because these computers are critical to the work I'm doing.Am working with two laptops, Dell Latitude D600's (I know, I know--they're old. New ones have been approved as soon as budget frees up the order.) Specs are as follows:1.60 Ghz processor; 27 Gb hard drive; 599 Mhz, 256 MB RAM, running Windows XP Pro w/Service Pk 3We use one of the laptops as our main unit, and the other is our backup. About 3 wks back, our main unit suddenly came up with the BSOD on boot-up, with the following error message:mrxdav.sysDriver unloaded without cancelling pending operations.We hadn't added anything as far as software or hardware is concerned, and hadn't changed anything save for adding new text files via an application we run. Switched over to our backup laptop, and that ran fine for the past weeks, but now we're getting the same BSOD and error message on that unit as well. I was able to get the backup machine to boot up and function normally after about 100 reboots the other day, and it ran for the entire day without any trouble once it loaded everything.How do we get this straightened out? We don't have an IT person--just a couple of folks who know a bit more than just how to turn a computer off and on. I've run a clean-up/management application (I-Obit AdvancedCare) to clean up any registry errors, etc., but that hasn't solved the problem.

http://support.microsoft.com/kb/832143This KB article indicates that the problem is connected with too-long file names relating to networking. Unfortunately for you, the hotfix is pre-Service Pack 3 and since you have SP3, that won't help you. Further Googling around shows that the mrxdav.sys error is related to the WebDAV service and turning off that service solved the issue for some people.Start>Run>services.msc [OK]Scroll down to the WebClient Service, stop it, and change its Startup state to "Disabled".As a cautionary note, you shouldn't be using another elderly laptop for backup. Here are some suggestions for backup strategies:http://www.elephantboycomputers.com/page2.html#Backing_UpMS-MVP - Elephant Boy Computers - Don't Panic!

Thanks for the info, Malkeleah...but it looks like I've got bigger problems than I thought. (BTW, when I used the term 'backup', I meant that we use the second ancient laptop in case something physically malfunctions on the primary ancient one--I do back-up our files, applications etc. to external media (DVDs) after each use of the machine, which is generally only one day per week. We run animal electronic ID info through a custom application that was created for us back when we had an actual IT tech on board. They wouldn't pay him enough, though, so he bailed for a company that would.)Did what you suggested to both machines, and at first it looked like it did the trick--machines booted up and didn't go directly to the BSOD and mrxdav.sys error. After checking to make sure that everything was functioning (apps, etc.), I shut both machines down. A bit later, I restarted the machine that had developed the problem this week to do some cleanup work in one of my text files, and it looked like things were still good. But then my desktop came up, and instead of everything loading, I got this message:Windows Application Error: The application failed to initialize properly (0x0000017). Click on OK to terminate the application. Clicking OK made the error message disapper, but then nothing else loaded onto the desktop. Rebooted the machine several more times, and each time I got another error message; each one had a different title, but all had the same message about the application not initializing, and the (0x0000017) code. Did a system restart to the last known good configuration, and the original BSOD/mrxdav error came up. Did a system restore to the last day it worked OK. Got a new error message on bootup: PDVDDXSrv.exe - Bad Image: The application or DLL C:\Program Files\Cyberlink\PowerDVDDX\MSVCP71.dll is not a valid Windows image. Please check this against your installation diskette. (Don't have installation diskette here; I'll have to contact our administration office next week to get hold of the actual software.) So while the BSOD/mrxdav error has gone away now, it looks like there's still a mess on board. Any other ideas on how to get this thing back to normal? Haven't messed with the other machine again--have my plate full with this one. I wouldn't be so worried if I wasn't handing the stuff over to a substitute tech this coming week because I have to go out of town for a wedding--I can't give her equipment that's not functioning correctly, and I've only got two more days to get something straightened out.Have run Malwarebytes & IObit Advanced System Care 3.6, and no malware/spyware was ID'd. Run Symantec Virus Shield and update with each use of machine, but I suppose something still could have gotten through... I do have access to Hijack This, but I've never used it because I don't have any idea what to do with the info once the application created a report.

The error message indicates infection but since you've scanned, it is more probable that the master laptop is experiencing hardware issues and/or the operating system has become corrupted. If you are imaging to the second laptop, that would explain why you're seeing the same issues on it. Best free up some of that budget money now.http://www.elephantboycomputers.com/page2.html#Hardware_TshootStart with the RAM and then do the hard drive.If the hardware tests good, back up your data if necessary and do a clean install of Windows.MS-MVP - Elephant Boy Computers - Don't Panic!