Windows 7 update fails. No error code

That's normal.
All I can think is to clear the various stores, and see if that helps.
We'll do it one at a time...

Please run thefollowing commands in an Elevated Command Prompt



NET STOP CRYPTSVC
REN C:\WINDOWS\SYSTEM32\CATROOT2 CATROOT2OLD
NET START CRYPTSVC



once complete,leave the system alone for at least an hour to rebuild the database, thenreboot.

Note that this may delete your Update History - but all updates will remaininstalled, and can be viewed in the Installed Updates listing.

After the reboot, do a new manual Check for Updates - what happens?

AH - that may give us a clue...

Please run the following commands - what happens?


NET STOP CRYPTSVC

esentutl /p%systemroot%\System32\catroot2\{F750E6C3-38EE-11D1-85E5-00C04FC295EE}\catdb

NET START CRYPTSVC

- post the results

Just in case, I ran Check for Updates for over 3 hours this morning with no success.
The esentutl attempt failed, screen shot attached.
Note, after renaming, catroot2 was not re-created, it does not exist.
Could there be some service that should be running that somehow has been disabled, but does not affect anything else?

If the catroot2 folder is completely missing, then there are serious problems with the OS, and it may be better to contemplate a repair install.