Win 7 x64 SP1 and Update Tool 800B0100

I can't see anything wrong in the CBS.log - the SFC is certainly clear, and the background errors in CBS are minor.

What is the error message on installing SP1 now?

Please post the C:\Windows\windowsupdate.log file and I'll see if that gives me some inspiration.

Here's the detailed error that I can find...

Code:

2014-04-01 08:36:25:540  528 1214 Agent WARNING: Failed to evaluate Installed rule, updateId = {2A1234D0-3E2D-4D9E-AA5E-3430A20EDC11}.100, hr = 80242013
2014-04-01 08:36:26:959  528 1214 Agent WARNING: Failed to evaluate Installed rule, updateId = {818701AF-1182-45C2-BD1E-17068AD171D6}.101, hr = 80242013
2014-04-01 08:36:28:816  528 b04 AU Forced install timer expired for scheduled install
2014-04-01 08:36:28:816  528 b04 AU UpdateDownloadProperties: 0 download(s) are still in progress.
2014-04-01 08:36:28:816  528 b04 AU Setting AU scheduled install time to 2014-04-02 01:00:00
2014-04-01 08:36:28:816  528 b04 AU Successfully wrote event for AU health state:0
2014-04-01 08:36:30:657  528 1214 Handler FATAL: UH: 0x800f0818: EvaluateApplicability failed in CCbs::EvaluateApplicability
2014-04-01 08:36:30:727  528 1214 Agent WARNING: Failed to evaluate Installable rule, updateId = {F9164872-3E27-4410-B4FC-038814549BB1}.103, hr = 800F0818
2014-04-01 08:36:32:292  528 1214 Handler FATAL: UH: 0x800f0818: EvaluateApplicability failed in CCbs::EvaluateApplicability

I'll have to research this one.

Just a quickie...
Looks as if it may be corrupted downloads.
Try this...

This could be due to corruption in the SoftwareDistribution folder - the problem with that the conventional cure can lead to problems later on, if not handled properly, and you will lose your Update history (but the updates will still be installed, and viewable in the Installed Updates listing).

Open an Elevated Command Prompt
Run the following commands

NET STOP WUAUSERV
REN C:\WINDOWS\SoftwareDistribution SDOLD
NET START WUAUSERV

reboot
then wait 10 minutes, and open Windows Updates, and run a Check for Updates.

Install only the oldest update found - and reboot once installed
then go back to Windows updates and install the others one at a time (if the first installed!) with reboots in between.

PLease try installing from the standalone installer - Download Windows 7 and Windows Server 2008 R2 Service Pack 1 (KB976932) from Official Microsoft Download Centre - windows6.1-KB976932-X64.exe