PCR descriptor - Loader Error 3 - after W2k Pro SP4 Rollup

I have a Dell Latitude D800 laptop with W2k Pro. Last night I went to
windowsupdate.microsoft.com and saw the SP4 rollup, about 32mb.

After installing the SP4 Rollup and rebooting, the vertical ASCII bars at
the bottom of the Windows starting up... screen get about 80% to 90% to the
end and then I get the following:

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Couldn't allocate PCR descriptor

Windows 2000 could not start because of an error in the software.
Please report this problem as :
Loader error 3.
Please contact your support person to report this problem.
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All of the Advanced Startup options will result in this error. Even Safe Mode.

Using Recovery Console I placed a /sos at the end of my startup OS in
boot.ini.

I could then see that the last driver to load before getting this error was
the agp440.sys driver. So I did a 'disable agp440' and rebooted. Now the last
driver that loads is the tiumflt.sys driver. Obviously agp440 is not the
cause of this problem. It must be in the driver loaded after
agp440/tiumflt.sys but I don't know how to determine what that is.

I still get the error about the PCR descriptor.

I went into the $Uninstall...$\spuninst folder and tried to uninstall the
rollup, but evidently Recovery Console blocks that kind of activity...

Most of what is on this laptop has been backed up, but there are some fairly
important documents and images from recent that are important to me. My
installations of the software I use is also important so I am hoping one of
you might know how to get this to a point where Windows will load.

I have the W2k Pro Full setup CD. I do not have an Upgrade CD. Someone
mentioned I might want to force an upgrade install but that sounds like a bad
idea to me at this point.

Thank you for any ideas.

Bob Kramer