C000021A BSOD - Hits 6 PCs at once.

[XDroidie626]

Okay community, I have a strange but interesting question for you.

At work there are 6 PCs we call Bonders, they control furnaces via WinCC and run WinXP (There isolated), and on thursday we had a weird issue were all 6 went down together with the same error, C000021A.

Now I have researched this issue of course and it turns out its to do with WinLogon and some other core files.

Now I have got 3 working thankfully via System restore, these work perfectly now but there are 3 still affected and we cant use restore because who ever built them decided to turn restore points off (Very strange)

Here is what I have tried.

 

F-Secure Scanning and also disabling.

Removing GPU drivers.

chkdsk /f /r /x (Starts a 5 phase scan).

sfc /scannow (Wont work thanks to XP not auto detecting CD)

Cloning a working PC to another (They are all identical in hardware)

Removing the standard user (Easiest way to find the error) and allowing Windows to rebuild the user.

 

Now we can do XP recovery via CD but it can be risky as these are mission critical PCs so errors can cause issues, although we do have 1 PC imaged.

 

What could you suggest for this error?

 

Thanks