The updates themselves shouldn't have that effect, my Win7 laptop is fully updated and has no performance issues. However it does have a known problem where the Windows updater gets stuck, and that can have an adverse effect. It's quite simple to check for - once the computer has run for several minutes and settled to its normal operating state where you notice it feels slower than it used to, Ctrl-Alt-Del and check the CPU usage in Task Manager. If it is stuck at a particular value, say 25% or even 50%, then possibly the updater has got stuck endlessly searching for updates.
If you find this, you can confirm if it's the updater by going to the Resource Monitor, on the Performance tab, and on the CPU tab look for wuauserv in the services. If it shows as taking the %CPU, this is the problem. Alternatively you can go to Windows Update and temporarily turn updating off, reboot and check CPU usage again. If your system has the updater problem, this is also a temporary work-around.
Please let us know if you discover this is the cause of the issue. People have reported differing degrees of success with different procedures for dealing with that particular issue, and if you don't actually see the updater fault, we'll need to look further.
Edited by Platypus, 14 December 2017 - 04:26 PM.