Bad Blue Screen STOP Errors In WinNT4

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STOP 0x0A IRQL_NOT_LESS_OR_EQUAL ntoskrnl.exe

See the following links for more information and a few more options:

http://www.osr.com/ddk/bccodes_71bb.htm

http://www.computerhope.com/issues/ch000365.htm

(The following applies to Windows 2000, but some causes may still apply.)

http://msdn.microsoft.com/library/default.asp?url=/libra ry/en-us/w2kmsgs/6077.asp

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In reference to:

KMODE_EXCEPTION_NOT_HANDLED

This is a very common bug code. Usually the exception address pinpoints the driver or function that caused the problem. Always note
this address as well as the link date of the driver or image that contains this address. A common error is exception code 0x80000003.
This error means a hard-coded breakpoint or assertion was hit, but the system was booted with the /NODEBUG switch. This problem should not
occur very often. If it occurs repeatedly, make sure a debugger is connected and the system is booted with the /DEBUG switch.

On non-Intel systems, if the address of the exception is 0XBFC0304, the bug code is the result of a cache-parity error on the CPU. If the
problem reoccurs frequently, contact the hardware manufacturer.

http://www.sgi-hi.com/files/nt_bug_codes.htm

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Another very strong possibility, especially since all research does indeed point to hardware compatibility and/or hardware issues:

When you upgrade a PC to dual processor by adding a second processor, you need to change some of the Windows NT 4.0 system files. There are generally two ways to do this:

Reinstall Windows NT 4.0 from the original source, usually a CD, and then re-apply all applicable Service Packs. This works best if your system was originally installed from the CD.

Many PCs come with the system preinstalled with many third-party drivers that are not included on the original CD media. In such cases reinstalling from the original CD can be complex or even fail.

Use the UPTOMP utility in the Windows NT 4.0 Resource Kit. This method is generally faster (and more successful :-) if you follow the procedure below.

Upgrading with UPTOMP.EXE

If your running system was installed directly from a base CD or from a CD that has combined the base CD withthe same service pack as is running, use the CD directly.

Otherwise, create a temporary directory to hold the service pack files (e.g. temp/sp6). If you have the Service Pack as a single EXE file, expand the service pack to the temp directory (using "servicepack.exe /X"). If you have the Service Pack as a CD, copy the I386 directory to the temp directory.

Copy the \I386\TXTSETUP.SIF from the base Windows NT 4.0 install CD to the directory created above. This file tells UPTOMP which specific hardware specific files to update.

Start UPTOMP.EXE.

Select the Multi-processor HAL (Hardware Abstraction Layer) to use (usually "MPS Multiprocessor").

Enter the full path to the service pack files (e.g. "c\temp\sp6") or the path to the CD (e.g. "E:\I386"). Click OK.

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For the system files, enter the full path to the service pack as in (6). Re-select the MP hal to use (usually "MPS Multiprocessor"). Click on OK.

Click OK to the information/warning message.

Note: Do not attempt to copy the files yourself. UPTOMP has some internal knowledge of what files to copy for each specific HAL.

Source:

"Upgrading to Dual Processor with Windows NT 4.0"

http://windows.berkeley.edu/docs/uptomp.html

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And a final bit of information:

Windows NT detects the capabilities of your motherboard and system. If you install Windows NT with two CPUs, the operating system will install flawlessly. Windows NT will auto-detect if one CPU is removed. If youinstall Windows NT with one CPU, then it is a different issue. Windows NT will detect a single CPU system and a single CPU hardware abstraction layer (HAL) will be installed. When a second CPU is installed on the motherboard, Windows NT will not recognize the second CPU. Windows NT's HAL will have to be modified using the Microsoft Resource Kit HAL conversion utility program, or a complete re-installation of Windows NT with two processors is required.

Therefore, the sequence of all of your installations and/or upgrades is (was) critical. It appears that if even one change was made out of the proper sequence, these errors will result.

Best of luck,

Maxwell

Sorry, but this was general info from public sources that proved not specific enough to significantly attack a pretty deep-rooted problem.

This answer gave me a way forward. I tried other fixes (such as re-seating the boards just in case) but I believe SiSoft's Sandra made the difference. It spotted the video card did not have an IRQ allocated. This was OK at delivery but a later Service Pack presumably introduced something that couldn't handle this. The PCI video board had a jumper to allocate an IRQ. A difficult problem to reproduce, but I have had no failures in three weeks, so it looks to be fixed. Many thanks, Tim.