PC security guides

Plain-English answers to the questions people ask when a computer starts acting strange: who else is using it, what is running in the background, and how to get it back.

• How to tell if your computer is secretly mining cryptocurrencyThe warning signs of a hidden crypto miner on Windows, how to check for one in five minutes with tools already on your PC, and what to do if you find one.
• How to remove a hidden crypto miner from WindowsStep by step: stop a cryptominer, remove what restarts it, undo the changes it made to Microsoft Defender, and make sure it does not come back.
• Why is my CPU at 100% when I'm not doing anything?High CPU and loud fans with nothing open: the normal Windows causes that go away on their own, the ones you can fix, and the signs it is something that should not be there.
• How to tell if someone is remotely accessing your computerThe signs someone has remote access to your Windows PC, the five places to check for remote-control tools and extra accounts, and what to do right away if you find one.
• Is something selling your internet connection? How to find proxywareWhat proxyware is, why it ends up on PCs without permission, the signs your connection is being resold to strangers, and how to find and remove it on Windows.