Threats

How to Recover from a Virus Attack

By Sam Adams

For your computer to get infected with a virus, all it takes is the unknowing click of an email attachment.  An infection can even happen if a friend's computer picks up a virus and then unwittingly passes it on to you. A virus can cause your PC to act in strange ways -- from going totally dark to not launching programs to mysteriously misplacing files.

A computer virus is just what it sounds like: A program that alters the way your computer operates, affects its overall wellbeing, and spreads like wildfire among computers that "come into contact" with each other via the Internet.

Once a virus sidesteps your home computer's security defenses -- that is if you have some in place -- it can quickly rip through your system, destroying files, corrupting data, and rendering applications useless. If your family is like most, you can't stand for your computer to be sluggish, let alone crippled indefinitely.

Sometimes even if you have virus-protection software installed you can still be at risk, such as when you don't automatically get updates to protect you from the latest threats. If your computer is ever hit by the latest virus to spread across the Internet, here's what to do get back online and to prevent it from happening again:

1. Disconnect and isolate

   If every person in your sister's email address book got infected by malicious code -- a.k.a. a virus -- then chances are so did you. If you suspect that your computer has been attacked by a virus then physically disconnect the machine. It's as if you are putting your infected computer into quarantine. An infected machine can endanger other computers.

2. Clean up

   Once your computer has been disconnected, you need to remove the malicious code. You should use removal tools written for the specific virus. Your anti-virus software should have updates or patches available for the specific security threat. If this software hasn't been updated recently, be sure to do so.

3. Reinstall

   After a virus attack, the damage could range from your file names being changed to obliterated files to permanently disabled software applications. Before using your computer again, you need to restore your computer to its original condition.

   The extent of damage depends on the particular virus. If your operating system is completely destroyed, you'll need to reinstall it. Use the restore CD that came with your computer to return to its original configuration. There is one catch: You will lose any applications you may have installed or data files you may have saved. Before you begin the reinstallation process, make sure you have all the necessary information handy that you'll need to get fully up and running again, such as the original software CDs, licenses, registration data, and serial numbers.  You are essentially starting over. 

4. Scan for viruses

   After restoring and reinstalling your operating system or programs, and documents, install antivirus software if you don't have it already. Then use the software to scan your entire computer, including all files and documents, for viruses. Use the most recent virus definitions available for your antivirus software.

5. Back up your data

   If you have been diligent about backing up your files -- from emails to documents and your web site bookmarks -- all is not lost. If you haven't followed a regular schedule of backing up on CDs, an external hard drive or remote storage site, your files will be permanently lost. If this is the case, learn from your mistake and make sure to back up regularly from now on. Keep in mind, not all viruses target data files -- some attack only applications.

6. Prevent future attacks

   Above all, learn from this experience. If a virus penetrated your defenses, ask yourself why your previous security measures weren't effective. Have you been diligent about updating virus definitions and security patches? Are you opening suspicious emails? Are files being downloaded without being scanned first? Now is an ideal time to comb through, edit, and reinforce your home computer security policy.

   To play it safe, always run antivirus software and keep virus definitions current. Ensure security patches are up-to-date. Next, you will want to change all of your passwords - for your ISP and email accounts, as well as for web sites where you have visited and shopped. Some viruses can capture or crack passwords, leading to future vulnerabilities. If you take these steps, you won't be caught off guard in the future: Prevention is always the best security policy.