On 2K machines what I have done to get 'em fixed... Steps off the top of my head... If the machine has vital local info dupe the hard drive with Ghost, GPARTED (great utility), or some other imaging software in case this doesn't work
Boot of a 2K SP4 install disk (if you don't have a SP4 version you could slipstream one).
Go into Repair the W2K installation to recovery console
Log in (need to know local administrator account or you'll need other tools to go in

)
at the prompt type fixboot to repair the MBR
Bounce the machine
Boot again off the CD
Choose to repair the Win2K - it will ask you a couple times to make sure. If you don't have an ERD it will
usually find the C:\WINNT default folder. Or you can make an ERD off an identical operating machine (didn't need to but should work)
When offered to Auto or Manual repair, chose M and hit enter (with all options selected)
You'll be prompted to overwite files - choose A to overwrite all. This will overwrite the files - all except some which error which are the IE6 files which you will skip.
Essentially you are reloading ALL of the system files on the machine - with IE
5 installed. Once done, reboot into the logon
Sometimes you may need to run the file repair process twice (happened one out of three times)
So now you have a vanilla reinstall of SP4 with IE5 and no hotfixes. Run the IE6.1 install from MS or break out your technet discs and fine the IE6 network install - run it..
Go and start the Windows Update and download the newer Window BITS tool (it will walk you through) but do not install the Microsoft Update. Those of you with WUSs servers or doing things through a GPO can alter accordingly
Run all of the updates except for the 931786 (it's 9317xx - I remember that much).
I had 3 computers to do this to today and was able to recover two of them. One machine lost all of its fonts and IE/Outlook as well as a terminal emulation app are fubared. I would consider running the process again but I started a little vacation today so one of the other guys will do it Monday
Unfortunately, limping some old machines through is necessary for specific application computability - otherwise they would be XP...
I have not heard of this impacting any of the 800 or so PCs (mostly XP) or servers 2K under my control

knock on wood
Anyone hear anything official from MS?