I came across an issue, for the second time, trying to install W7 clean. It won't run Windows update.
The reason it won't run Windows update is that IE8 is out of support and they block it from accessing the site. Now I've been round this loop before and you can't install IE11 (the only one now accessible), using IE8 as IE8 is blocked from downloading the updates.
My last machine in which I tried to force this became borked due to the WU tool I used breaking it and I had to update it to W10 in the end.
My solution is this. Download firefox from http://www.getfirefox.com
Make it your default browser
Paste this link into firefox. Best bet, navigate here and click on it in IE8 or use the link below. It won't render correctly in this post..
And install IE11. Because Firefox is the default browser it correctly downloads all the updates for IE11 and then IE11 itself.
You can then follow t he rest of the instructions in Method 1 in this link.
That did it for me.
Note you can't just install IE as it says in the start of Method 1 as IE8 is blocked...