• You experience new, prolonged slowdowns. This can be a sign that a malicious program is running in the background.
• You continually get pop-up ads that you can't make go away. This is a sure sign you have "adware," and possibly more, on your machine.
• You're being directed to sites you didn't intend to visit, or your search results are coming back funky. This is another sign that hackers have gotten to your machine.
So what do you do?
• Having anti-virus software here is hugely helpful. For one, it can identify known malicious programs and disable them. If the virus that has infected your machine isn't detected, many anti-virus vendors offer a service in which they can remotely take over your computer and delete the malware for a fee.
• You may have to reinstall your operating system if your computer is still experiencing problems. It's a good idea even if you believe you've cleaned up the mess because malware can still be hidden on your machine. You will need to back up your files before you do this.