If I may relate my experience, it may help others....
During a clean (new install){my fault, me bad
} of W2000 into my IBM 390e - after downloading SP4 - the attempt to download Windows Defender Beta 2 failed with the message to: "verify that you have sufficent privledges to start system services".Clicking "Retry" a couple of times, the download proceeded and was accepted.
I knew of the GUI+ problem and had already installed the needed files.
Upon reboot, the Error Code 0x800106ba - "problem caused windows defender to stop" came up. Using Administrative Tools to manually start service came up with this error: 2147942402 - "system cannot find file requested".
I came to find, upon checking MS update site to check update history; Backround Intelligent Transfer Service (BITS) 2.0 and WinHTTP 5.1 had failed to load successfully in past. The latest version of Windows Installer had installed tho.
I "redownloaded" the above files, but Defender still would not boot/start.
Going back to the MS site, I located and downloaded W2000 Service Pack 4 Rollup 1.
Upon reboot, Windows Defender was recognized, opened, allowed updates and conducted first full scan with no problems.
Somehow, the Rollup is not listed in AutoUpdate but is needed.
Thanks to everyone for all of the help in the past and I pray that this may help someone now - is the least I could do.
Respectfully,
LaughingMutt