Sometimes it’s difficult to tell when your computer is infected with a virus—some viruses make their presence felt immediately, while others are more subtle. If you’re noticing that your CD drive opens and closes mysteriously; some programs are unusually slow when opening; your firewall notifies you that applications on your computer are attempting to access the Internet and you know you didn’t tell them to; or your friends are getting emails from your address that you didn’t send, your computer may have a virus. Here’s what to do.
Disconnect your computer. If your computer is connected to the Internet, the virus may send information about you to a third party. It may also be able to infect other computers you’re networked with, so disconnect it from local area networks as well. Work quickly to isolate your computer as soon as possible, and you could minimize the damage.
Start your computer in Safe Mode. If your computer is infected, you may not be able to boot it back up normally. Try booting it in Safe Mode instead. When your computer starts, hit F5—or hit F8 and choose it manually.
Back up your data. Once you’ve got your computer booted up, back up all your critical data on a disc or flash drive. When you try to uninstall the virus, your data might be at risk—so you’ll need to make sure you don’t lose anything before you start. Before you re-install this data on your computer, you’ll need to scan the disc or drive to ensure it’s virus-free.
Get an antivirus program installed or updated. If you don’t have an antivirus program on your computer, install one. If you do, be sure it’s updated by going on the manufacturer’s website and checking for updates. Don’t do this from your computer—do it from a friend’s computer or an office computer. Download the updates onto a disc or flash drive and then install them on your computer. Once that’s done, run a scan.
When your antivirus software finds viruses on your computer, it will give you several options—including disinfecting infected files, quarantining files that may have been infected, and deleting worms and Trojan Horse viruses. All of these should be performed if needed.
Scan all media that may have been infected. If you’ve used discs, flash drives or other portable media in your computer while it was infected, these media may also be carrying the virus—and if you use them again, you could re-install the virus or cause it to infect another computer. Scan all portable media you’ve used while your computer was infected, including the one that contains your backup files.
Check your files. Once you’ve performed thorough scans of all media that might contain the virus, check to see if you can access your files. Some particularly malicious viruses can corrupt files completely during the infection process, so they can’t be retrieved even after the virus is removed. In rare cases, a virus cannot be removed completely from files, even after a scan. If this is the case, you’ll need to delete the files.
Check the antivirus software’s site again. Once your antivirus software has successfully removed the virus, you’ll need to check and see if your data is recoverable. It’s possible that the vendor will have utilities that can help you recover infected data. It may also provide you with information about the virus you encountered.
Contact a data recovery service. If your files have been corrupted and you can’t find a utility program on your antivirus vendor’s site that can help you repair the damage, contact a data recovery service. These companies may be able to help you retrieve your damaged data.
When a virus infects your computer, don’t panic. In the vast majority of cases, your data can be retrieved. If your computer hasn’t been infected, you can catch problems before they happen by installing antivirus software and ensuring it’s kept updated. You should also avoid downloading programs from unknown sources and opening unfamiliar emails—all of these things can invite viruses onto your computer. Run scans often and keep your antivirus software up to date, hopefully your computer will stay virus-free.
What to Do When Your Computer Catches a Virus