Is your computer running slow?
Does it take longer to start up?
It could be something minor, or it could mean hackers have gotten in and are recording your every keystroke.
Data Doctors expert Ken Colburn says most of the time, you'd never know the difference.
It can happen if you go to an unknown website. Or you could click on a link. Maybe it's a free download your child wanted. It could be something sent from a trusted friend who didn't know they'd been hacked.
Make sure your computer protection software is up to date.
If your computer is noticeably slower or you have other obvious signs, you may want to change passwords on a different computer.
And you should consider taking your computer to an expert to be scrubbed.
Click here for more ways to tell if your computer may have been hacked.