As of about 6 months ago I've been deploying PC's for customers who aren't comfortable with Windows 10 after all the nonsensical press about it spying on users, and they don't want Windows 8/8.1 either because of the UI, some just have software that the vendor hasn't tested on anything newer than Windows 7.
Each customer needs a different build of Windows with different preinstalled programs, so require different images to be installed from a WDS. While making the first of the base images, which I would then fork into different images for the different customers once updated, I noticed Windows 7 would just sit at trying to check for updates, seemingly never ending.
Now I knew Microsoft had released an update to Windows 7 update around the time of the Windows 10 launch so I checked my suspicions and yes, this update does resolve the never ending search for updates.
Once installed within a few minutes Windows 7 will find updates, you can grab the update below for x86, x64 Windows 7 and Server 2008 R2... and IA-64 if anyone actually still uses them:
Microsoft have now released a convenience rollup update for Windows 7 and Server 2008 R2 which can be found here and will allow you to get the latest updates up through to April 2016 patch Tuesday.