Expert: Carolyn Meinel - 7/28/2008

Question
hi

i scanned my computer with norton anti virus it found 2 downloader viruses and 1 backdoor trojan virus can you help me my computer is running very slow anti virus software won't remove them

Answer
Those viruses Norton found should be quarantined so they won't harm your computer. So the slowdown on your computer is probably caused by something else.

It is possible that your computer has adware or spyware installed. These aren't removed by antivirus-only programs because you typically install them yourself, although by accident. By this I mean you click on something in your web browser, or install a free program you download, and surprise, surprise, these things install somjething bad on your computer.

To get rid of adware and spyware, you need complete protection by something called an Internet security suite. If you already have Norton's security suite instead of just antivirus, then it should eradicate adawre and spyware, too. If you just have the antivirus, though, it would probably fix your problem to upgrade to the full Internet security suite.

If you want to try something free, instead, here's what will almost certainly work.

1) Download either Kapersky Internet Security, which offers a free 30 day trial at http://kapersky.com or F-Secure's Complete Internet security suite, which offers a free thirty day trial: https://store.f-secure.com/cgi-bin/dlreg/ml=EN?ID=FSISTB&desid=TRIAL

2) Disconnect from the Internet.

3) Uninstall your current antivirus. This is absolutely essential because otherwise it and F-Secure or Kapersky will fight each other and might crash your computer. It isn't good enough to just turn off your old antivirus because it probably has been crippled by your virus infection.

4) Install your Internet Security product. Download any updates available.

5) Run a complete scan of your computer. Follow any instructions it might give you.

6) Reboot.

If this works, you can either keep your new Internet Security product or uninstall it and reinstall your old antivirus from either a download of the latest version from their website (if that's how they sell it) or from the disk it was on when you bought it. Be sure to get all the latest updates right away. Usually antivirus companies are pretty good about updating their programs whenever some new attack becomes able to evade or cripple their product.

If you weren't running an antivirus program that includes antispyware protection and a firewall, then I recommend that you not reinstall your old program. Nowadays we need total protection, and this includes antispyware and a firewall.

7) To prevent future infections, don't use Internet Explorer, as it is susceptible to introducing viruses, adware and spyware into your computer. Instead you could use Firefox, free from Mozilla.org . Instead of using Outlook for email, you could use Thunderbird, free from Mozilla.org, or Eudora, free from Eudora.com .

If this doesn't work, sometime a Windows computer will run slowly simply because Windows is famous for self-destructing. Norton System Works usually can automatically fix these problems.