What could be causing these repeated BSOD's on these machines?

Hello Capperdog:

I would suspect a worm or other form of malware on your network.

How is your system security handled?

Do you have any anti-malware software on your network (i.e., anti-spyware, anti-virus, etc.)?

Have you scanned the problme machines for worms, viruses, root kits and other low forms of computer life?

wb

hmmm. the fact that this is occurring repeatedly on many different machines rules out several possibilities...
That particular BSOD can mean many things(like most windows errors!): The Microsoft KB article explains them - http://support.microsoft.com/kb/122926
It says:
This problem may occur if one or more of the following conditions exists:
•      Your computer is infected with a boot sector virus.
•      A device driver required by your boot controller is not configured to start at boot time or is corrupt.
•      A resource conflict exists between the boot controller and another controller in the system or between SCSI devices.
•      Drive translation is not being performed or was changed.
•      The boot volume is corrupt and cannot be mounted by Windows NT.
•      Information in the Windows NT registry about which device drivers load at start up is corrupt.
 
The one that springs out at me there is a resource conflict. If all of these systems have the same hardware, it might be helpful to remove each piece of non-dependent hardware one by one to narrow it down. As warrenbuckles says, it could also be a worm. That said, if your network isn't secure, BSODs are the least of your worries :)

~cheesygit182

P.S - Which STOP error exactly are you getting?

i would think that bad sectors on the disks would be the first cause; but sometimes the sectors are not bad, but the info in them.
this can be caused by bad contacts in cables or connectors, or even failing power supplies.
you can always test the problematic disk(s) (and controllers) with any of these :
http://www.hitachigst.com/hdd/support/download.htm                  Drive Fitness Test
http://www.maxtor.com/en/support/products/index.htm                  Maxtor & Quantum
http://www.fcpa.fujitsu.com/support/hard-drives/software_utilities.html#diagnostic Fujitsu
http://www.samsung.com/Products/HardDiskDrive/utilities/shdiag.htm      Samsung
http://www.seagate.com/support/seatools/index.html                  Seagate
http://support.wdc.com/download/#diagutils                        Western Digital
http://www.hgst.com/hdd/support/download.htm#DFT                  IBM & Hitachi             

Thanks for the many responses. Let me comment. Our network is very secure. This is a govenment facility and security is our utmost priority. All of our machines are running the very latest McAfee 8.0 Enterprise and are scanned often by our corporate IT group for Virus, Worms etc. I don't think this is the issue. To maybe narrow this down, most of the machines in question are Compaq d530's with the slimline Maxtor drives. Almost all of them. The others are HP XW4100's with various drives. I have scanned one of the Western Digital drives that was in one of the XW4100's with the WD tool listed by Nobus and the drive tested to be fine.

At the moment I do not have any machines that are down. I do have some that I have not replaced the hard drive in. Is there something I can check on these machines before I replace the drive?

Just to be clear,  the machines I have not replaced the drive in are up and operational at this time.

Just to let you know, I have a small computer shop and every single one of those slim Maxtor drives that has come in (about 10) have failed my hard drive diagnostics. It may not solve your problem, but I would replace all of those drives ASAP to avoid future issues.