Christophe,
I wanted to add this.... the W7Pro64 update process has become quite difficult, and it is because there is an automatic update that happens right after a clean install from the installer CD/DVD, which ruins the normal update process. The solution is below. Basically, you download two updates onto a thumb drive, and fully disconnect the target workstation from the internet before you start a proper clean install. If you happen to have a documents HDD in the workstation make sure to disconnect it from the SATA bus so you don't risk it and also so you don't have it trying to index itself while the updates are trying to go forward simultaneously.
After the clean install you then install both the updates from the thumb drive, which takes the Windows Update components in the System 32 folder forward in time beyond the bad auto-update. Thereafter you can proceed with reconnecting to the internet and getting updates without this issue blocking the process.
Doing a proper clean install is beyond the scope of what I can help you with here. Make sure to read up on how to ensure you get the little "system reserved" partition in place on the boot drive.
Here are two links for my breakthrough on the W7 Windows Update mess Microsoft created. They still have not fixed that as of a couple of days ago. It is inexcusable.....
google "Following a clean install, Windows Update remains at "Checking For Updates" forever" and you will find the link at the top. This also might work: HERE. The first page is really all you need. That is specifically for what to do during a clean install.
Microsoft finally provided a bit of help based on this solution, for fixing the issue after an install and when one can't get updates to install. I have wasted many hours over the past year due to this issue, and many have given up on W7 as a result of it..... Maybe that was the intent? Hard to believe, but they have been pushing W10 hard.
https://support.microsoft.com/en-us/kb/3200747
Best, Scott