"电脑防护基本知识20页PPT：预防与处理常见症状，免费工具分享"

The document "Basic Knowledge of Computer Protection (20 PPT slides)" provides essential information on protecting your computer from viruses and malware. The symptoms of a computer virus attack are outlined on the first page, including slow performance, prolonged program loading times, unusual error messages, and unexpected changes in disk space and memory. It also provides tips on preventing virus infections, such as installing antivirus software, avoiding unknown software, and regularly scanning for viruses. In the event of a virus infection, the document recommends turning off the computer, removing external storage media, and reconfiguring the system. Additionally, it introduces the "Windows Malicious Software Removal Tool" for Windows XP, 2000, and 2003. The document also mentions a free online virus scan service—Symantec's online virus scan. However, it seems that the content has been truncated or cut off, and the conclusion is missing before reaching the required word count of 2000 words.