Just in the last few days I have noticed that the screensaver is not always activating. I 've checked through Control Panel and it is still set to come on after ten minutes. But a few times I've been away from the screen for twenty minutes or more and the saver hasn't kicked in.
I've just installed a wireless keyboard and mouse, and also had to go into Safe Mode to run a virus check, but apart from this I can't think of anything I've done that was out of the ordinary. Ideas welcomed!

This has happened to me on occasion.

I find that changing the time (say to 5 min.) will reset it.

If this works at 5 min. then change it back to 10.

Will do!

Yes, seems that's fixed it. Thanks, jephree.

Glad it worked. Happens to me maybe twice a year. Don't know why. But never looked too far.

Makes you wonder just how many little ruses like this keep computers going all around the world.
Not that that's a question I'd really want answered.