Hardware Reference
In-Depth Information
Diagnosing and Fixing Malware Infections
Even if you have an antivirus application installed, it's not perfect. Occasionally a virus
or other malware may get around it, especially a new threat (and especially if you haven't
updated your defi nitions lately). When a system is infected with a virus, a worm, a Trojan
horse, or other malware, you may experience some of these symptoms, either immediately
or on a particular day or time when the malware triggers itself:
Your antivirus software may be disabled, and you can't re-enable it. Or, if you didn't
already have antivirus software and you're just now installing it, it may not install.
This is a very common side effect of virus infection, because it makes it diffi cult for
you to remove the virus.
Your system may run sluggishly, taking much longer than normal to open windows or
applications. Many malware infections bog down a system or cripple it.
CPU and memory usage may be high even though you aren't doing anything that
would cause them to act in this manner. This can happen if the malware is hijacking
your system for its own computing purposes.
A warning or message box may appear onscreen and refuse to go away. For example,
there may be a message that your system is infected with a virus and demanding that
you enter a credit card to “buy” software that will fi x the problem.
Your friends may let you know that they have been receiving strange emails from you
that you didn't send.
When you use your web browser, you may be bombarded with pop-up ads.
If you start experiencing these symptoms, your own antivirus program may not be much
help because a virus may have gotten around it and disabled it. If it's running—great. Do a
full virus scan immediately.
If you can't use your local antivirus program, your best bet is an online virus checker.
Trend Micro offers a good free one at
http://housecall.trendmicro.com
, for example.
Scan your system with that, and then follow the advice the scanner recommends. If the
system is infected to the point that it won't operate even to open a web browser, try booting
into Safe Mode with Networking. Doing so may disable some of the virus's components
temporarily. If you still can't rid of the virus, you may need to consult an IT professional at
your local computer shop.
After you've removed the infection, you may need to repair or reinstall your antivirus
software and download updates to it.
Summary
In this chapter, you learned about several types of computer security. You learned about
measures for preventing hardware and data theft and how to create effective passwords
for access control. You learned how to control data and usage permissions including fi le
