Periodically I get a panicked call from my mum because her computer is saying it's got a virus and she needs to renew her antivirus in order to fix it. She's on a licensed copy of Windows which has built in antivirus. I go through the motions of checking for infection (or I did the first few times), but it invariably is because someone has installed some McAfee product that starts throwing up alarming pop-ups in an attempt to trick her into paying them. I uninstall the crapware and she's fine again for a few months.
The fact that she (or probably my kids) installs software that bundles McAfee trialware is obviously the root problem but my attempts to prevent that in the past have caused more issues. Yes, she'll probably get a real infection at some point and I do what I can to make sure she has adequate backups.
My question is: Can I at least set something up that will block McAfee products from being installed? She doesn't need them. They don't add any value, and they cost me a few hours of my time every few months.