I had to reinstall Win7 because my HD died. It installed OK and went through many updates, but when it came to the IE11 update, the update failed. I got a copy of IE11 and tried to install it and that failed, because of some missing updates. Help! IE8 works, sometimes, but acts flaky.
Take this as a sign to install Google Chrome instead. 
Okay, serious answer time: are you installing the correct version? There are 32 bit and 64 bit versions and you need to install the correct version for your system.
Here is the Microsoft page you should visit.
The Win7 update thing hit a catastrophic fail toward end of life for the OS. I feel your pain - one of my laptops runs Win7, and it hosed one, and the other simply won’t accept the update.
My advice is to updgrade to Win10 (which you may be able to do free of cost).
It actually broke a number of times for a number of different reasons (not really important here, but ask if interested). I’d suggest WSUS Offline Update which is a convenience wrapper around an official Microsoft method.
There are a number of “workarounds” which are almost always of the form “download these 2 or 3 special files from Microsoft, run them one at a time with a reboot in between, then sacrifice a rubber chicken…”
As I do a number of “wipe and start fresh” Windows 7 installs each week, I find WSUS Offline to be the most reliable method (and only needing to download the updates once for all N machines). Sure beats a countertop with a dozen systems all going “Checking for updates” for the last 3 hours without doing anything.
Here is C|Net on that very subject. I used the technique last year when I bought a refurb with Win7 and waited a week too late to catch the free upgrade window closing.