I've done several Win 7 rebuilds. With a reasonably high speed connection (and I don't think that's the issue), running through all the updates takes frickin' forever! It's a hot mess!
Looks like the trick is to install Windows 7 SP2, err, I mean the update rollup package to an SP1 box available here:
https://blogs.technet.microsoft.com/wind...dows-7-and-8-1/And soon it will be better via Windows Update as the cumulative strategy for Windows 10 is being implemented for 7 and 8.1.
http://arstechnica.com/business/2016/08/windows-7-8-1-moving-to-windows-10s-cumulative-update-model/