I was having similar issue a couple of days ago.
I tried the troubleshooter...reset Windows Update service...reset IE...reset the Windows Update Agent...fooled around with the Win 7 registry entries per one suggestion...and so on, all for naught. When I turned the system off yesterday, I could not even install any type of update, whether it was standalone installer or not.
This morning, I turn the system on...go to Windows Update and it reflects some update pending (probably one of the standalones that I tried). I was shocked but the download/install proceeded as it should have. I then saw that I had 90 critical updates awaiting some action...I downloaded/installed all 90 via WU, rebooted the system a couple of times when prompted...downloaded a couple of new critical updates/rebooted...downloaded a MS NET update/rebooted...and all is golden today .
If I were to suggest anything...I would not know where to begin, sorry .
There are a ton of topics in Win 7 dealing with Windows Update issues...you may want to do a search through those and get some ideas of how you might proceed.
PS: My check for updates and total install time today was less than an hour.
Edited by hamluis, 05 August 2016 - 12:29 PM.