It seems Microsoft has changed the way Windows Update client downloads and installs updates from Microsoft servers and only the new updated client is able to download updates from the servers, that's why the older versions of Windows Update client are unable to download updates from Microsoft servers.
If the new updates which upgrade Windows Update client version, are not installed in a Windows 7 machine, it starts giving this annoying issue and the Windows Update program hangs at "Checking for updates" screen and never downloads updates from Microsoft servers.
Does my computer keeps updating
This is the best and easiest solution to fix this problem!
You just need to install the required updates manually which upgrade the Windows Update client program and once you install these updates, Windows Update will be able to download and install updates from Microsoft servers without any problem.
It also affects overall system performance and if you check Task Manager, the process occupies high CPU resources and memory usage.
Most of the times this issue occurs after a fresh/clean installation of Windows 7.
If you can’t install i Tunes on your Windows PC, or if you see “error 2” or "Apple Application Support was not found" after you install the software, follow the steps below in order.
If you see a different error when trying to launch i Tunes, learn how to fix unexpected quits or launch issues.
If you see an "Windows installer package" alert message, follow these steps to try to repair the software through the Windows Control Panel.
If the steps in these articles don't help you fix the issue, you might be able to find a solution through a search of the Microsoft support website.
Actually Microsoft has released a few updates for the Windows Update client program.