Spammers frequently use other computers, referred to as "zombies," to rapidly disperse mass emails without compromising their own identities and to evade spam blacklists. Prior to becoming a zombie computer, your computer must be infected by a worm or trojan that allows the spammer to gain control of your system. If you do not regularly update your Windows operating system and your antivirus software, actively run a firewall or take other basic security measures, it is possible that your computer is sending spam.
Check your email for bounced-back emails in your inbox or trash. Examine any "Delivery Failure" notices you receive. Check the header, the content of the message and the recipient.
Examine your computer for intense resource usage. Hold down "Ctrl" + "Alt" + "Del" at the same time, then select "Task Manager." Click on the "Performance" tab and check the "CPU usage." A high percentage of CPU usage may indicate that your computer has been infected.
Click on the "Networking" tab in Task Manager. Examine your "Network Utilization," and determine how often your computer is using your Internet connection. A high, consistent bandwidth usage may indicate that your computer is sending spam.
Try to update your antivirus definitions or to install an antivirus suite if you do not currently have one installed. Perform a full scan on your computer, if possible.
Tips & Warnings
- If you cannot update or scan with your antivirus software, your computer has likely been compromised by a trojan or virus. Physically disconnect your computer from the Internet by unplugging the network cable, shutting down the modem and router or unplugging the dial up modem.
- Always install the latest Windows updates. Keep your antivirus software up-to-date, and enable a firewall to protect your computer from trojans and other security risks.
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