What version and edition of Windows are you using? And what do you mean by "block them"? Only install them when you manually download and install them, not automatically?
This is for windows 10 (the gpedit.msc setting is only for win 10 pro or above not home users so if you don't have pro or above try downloading to tool to hide updates!)
Bah. I configured the updates to notify me to download and notify me to install but when I clicked check for updates, the updates started downloading by automatically and then they installed automatically!
I have pro and like I said I configured them to notify me before install and before download but they downloaded and installed automatically when I checked for updates!!
Well that's how I have my Windows 10 Pro configured and to be honest it's not a problem. The "main" issue for me is that it would nag me with a restart prompt that I would delay to 4 hours (the maximum) everytime back in the Windows 7 era. But since Windows 8, the updates install, and when I'm about to leave, go to bed, etc. I restart my computer to install the updates, then shut it down and leave.
Found out you need to check for updates at least once after configuring updates. After that your configurations will be applied to future updates. So the setting does work properly.