A BBC report said that the company had now changed the functionality of the pop-up that was used to encourage users to upgrade to Windows 10.
The red X at the right-hand top corner is normally used to close the pop-up, but the BBC said now clicking there activated the upgrade, rather than closing the pop-up.
One can only avoid the upgrade when another pop-up appears at the time scheduled on the first pop-up. The instructions provided by Microsoft are not exactly simple and will take up a fair amount of time.
The BBC said Brad Chacos, a senior editor at PC World, had described this latest Microsoft move as a "nasty trick."
The only way to avoid an upgrade to Windows 10 appears to be by setting one's PC which runs Windows 7, 8 or 8.1, to use manual updates, as iTWire has outlined.
And this means one has to be vigilant about checking manually for updates every now and then in order to avoid being caught out when a serious vulnerability is patched.