Tried many things, still error 800736B3

CheckSUR is the System Update Readiness Tool - KB 974821 - which you downloaded, and produces the CheckSUR.log files.
There's been a new release of the tool this week - please download the new one, run it, and upload the new log.


Please download and save the CheckSUR tool from http://support.microsoft.com/kb/947821
(you'll need to look in the details for Windows 7, downloading from the Microsoft Download Center)

Run it - The tool can take anywhere from 5 mins to a couple of hours to run (or 'Install') depending on how much it has to do, and may exit silently - it may appear to freeze for most of that time, but be patient.
The result is logged in the C:\Windows\Logs\CBS\CheckSUR.log file - and an archive …\checksur.persist.log file

Then zip the CheckSUR.log and upload it to your SkyDrive Public folder so I can take a look - post a link in your reply.

You have significant registry corruption

Code:

Checking Package Watchlist
(f) CBS Watchlist Package Missing 0x80070002 Microsoft-Windows-FailoverCluster-Core-WOW64-Package~31bf3856ad364e35~amd64~~0.0.0.0 Package_6_for_KB2654428~31bf3856ad364e35~amd64~~6.1.1.0 Package registry presence failed, possibly an orphaned package on package watchlist
(f) CBS Watchlist Package Missing 0x80070002 Microsoft-Windows-Foundation-Package~31bf3856ad364e35~amd64~~0.0.0.0 Package_6_for_KB2654428~31bf3856ad364e35~amd64~~6.1.1.0 Package registry presence failed, possibly an orphaned package on package watchlist
(f) CBS Watchlist Package Missing 0x80070002 Microsoft-Windows-ServerCore-WOW64-Package~31bf3856ad364e35~amd64~~0.0.0.0 Package_6_for_KB2654428~31bf3856ad364e35~amd64~~6.1.1.0 Package registry presence failed, possibly an orphaned package on package watchlist
Checking Component Watchlist
(f) CBS Watchlist Component Missing 0x80070002 amd64_microsoft-windows-msvcrt_31bf3856ad364e35_0.0.0.0_none_514dc7519f6dcb19 Package_6_for_KB2654428~31bf3856ad364e35~amd64~~6.1.1.0 Package registry presence failed, possibly an orphaned package on package watchlist
(f) CBS Watchlist Component Missing 0x80070002 x86_microsoft-windows-msvcrt_31bf3856ad364e35_0.0.0.0_none_f52f2bcde71059e3 Package_6_for_KB2654428~31bf3856ad364e35~amd64~~6.1.1.0 Package registry presence failed, possibly an orphaned package on package watchlist
(f) CBS Watchlist Component Missing 0x80070002 x86_microsoft-windows-msvcrt_31bf3856ad364e35_0.0.0.0_none_f52f2bcde71059e3 Package_6_for_KB2654428~31bf3856ad364e35~amd64~~6.1.1.0 Package registry presence failed, possibly an orphaned package on package watchlist
(f) CBS Watchlist Component Missing 0x80070002 x86_microsoft-windows-msvcrt_31bf3856ad364e35_0.0.0.0_none_f52f2bcde71059e3 Package_6_for_KB2654428~31bf3856ad364e35~amd64~~6.1.1.0 Package registry presence failed, possibly an orphaned package on package watchlist
Checking Packages
(f) CBS Registry Error 0x00000002 Package_6_for_KB2654428~31bf3856ad364e35~amd64v~6.1.1.0 Microsoft\Windows\CurrentVersion\Component Based Servicing\Packages\ Failed to open store sub key
(f) CBS Registry Error 0x80070103 Package_for_KB2562937~31bf3856ad364e35~amd64~~6.1.1.0  failed to get owner for package.
(f) CSI Unable to Query Store Version 0x00000002

I have no idea how fixable this will be - but I'm willing to try it if you are :)

Please zip the COMPONENTS file ( C:\Windows\System32\config\COMPONENTS - no extension) to your desktop, then upload it to your SkyDrive, Dropbox, or other favoured fileshare site, and post a link.