Computer Viruses

           A Computer Virus is q software program that attaches itself to another program on the computer, and from one program to another. Some can go unnoticed for long periods of time because they are tied to a certain time or date before they become active. If transmitted unnoticed, viruses can damage data, cause computers to crash, or display bothersome or offensive messages. Avoiding computer virus infection is important.

              The danger of viruses is steadily increasing. New ones appear frequently, and their sophistication is also increasing, making them more and more difficult to detect. Viruses now constitute a major threat to both individual and corporate users. This chapter describes the measures to be taken in order to minimize the virus threat and keep your system safe. It also provides a list of popular virus detection and rem oval software.

• “File Copied” message appears without the user having invoked a copy command.
• Unexplained hard disk drive activity light or floppy disk drive activity light going on when the disk is not being accessed by the user.
• Reduction in the amount of RAM available.
• Failure of a memory-resident program to operate properly.
• Slow or bizarre system behavior.
• Bad clusters appearing on the disk regularly.
• Volume labels altered.
• Increased number of files on disk.
• Increase in size of executable program.
• Change in a file's date or time stamp, without the user having modified the file.
• Programs taking longer than normal time to load.
• Program running slower.
• Program or data file corruption or disappearance.
• When and executable file is invoked, and error message appears.
• The icons of applications/Programs charges.
• Files with unknown extensions like .eml are created automatically.
• Mails with attachments of Files with extensions like .vbs.