Several Security Updates Fail to Install - Need help

[Thenin]

I'm running 64-bit Windows 7 Pro. The last several security (and quality) updates keep failing every time.

KB4074598 (February 13, 2018) fails with error: 80070002

KB4041681 (October 10, 2017) &
KB4056894 (January 4, 2018) &
KB4057400 (January 19, 2018) &
... all fail with error: 8024200D

KB4048957 (November 14, 2017) fails with error: 80242FFF

I've run Microsoft's Update Fix Tool, but it made no difference. I ensure that my antivirus and even my firewall are disabled when I try to install these. It doesn't matter. I've also run SFC /SCANNOW and then SFCFix 3.0, and except for the fact that I installed themeui.dll back when it ran XP, that's the only error SFC found.

How should I proceed, please?

 

[Thenin]

Oh, and I tried renaming both the C:\Windows\SoftwareDistribution folder and the C:\Windows\System32\catroot2 folders. Windows Update reported that No updates had ever been installed, of course. But this didn't make any difference.

I also tried stopping the Windows Update service and installing some of these updates manually. This never worked either, so I didn't bother trying them all.