Code 800B0100 : Windows Update encountered an unknown error.

Download:Download: Security Update for Windows 7 for x64-based Systems (KB2579686) - Microsoft Download Center - Download Details
Create the directory C:\Windows\CheckSur\packages
Copy the downloaded msu files there
Re-run System Update Readiness Tool

Then,
Open up a command prompt as admin and run: "net stop wuauserv"
Then navigated to C:\Windows\SoftwareDistribution and deleted the contents of the download folder as well as "C:\Windows\SoftwareDistribution\DataStore\DataStore.edb"
(note, this erases your update history)

Then open up a command prompt as admin and run: "net start wuauserv"

Reboot
Re-run windows update.

First of all browse to the directory "C:\Windows\Logs\CBS\"
Is there more than one version of a CheckSUR.log file?
For example it might have a -2, _2, or just 2 appended to the file name: CheckSUR-2.log
If there is only one log delete "CheckSUR.log" delete it, and re-run the System Update Readiness Tool. The last log posted was not up-to date which would explain the file was last modified 2 hours ago as you stated in your post yesterday.

That is strange!
It says there are no errors.

Code:

=================================
Checking System Update Readiness.
Binary Version 6.1.7601.21645
Package Version 16.0
2012-10-10 17:30

Checking Windows Servicing Packages

Checking Package Manifests and Catalogs

Checking Package Watchlist

Checking Component Watchlist

Checking Packages

Checking Component Store

Summary:
Seconds executed: 494
 No errors detected

Was it KB2579686 that wouldn't install?

If so restart your computer and try installing it from here:
Download: Security Update for Windows 7 for x64-based Systems (KB2579686) - Microsoft Download Center - Download Details

Broosh said:

Code 8024200D

and yes, it was KB2579686.


One quick question, am I going to have to manually download every single update for now on? Or do you think the fact that I finally got SP1 to go through will help?

This is the only update that wont install then you shouldn't have any more problems in the future.

As for manually installing the hotfix, the error 8024200D relates to an improperly downloaded or installed update.

For now just try to manually install it and post back if you have success.