When a computer is infected by virus some signs indicate the infection. Some of the symptoms are as follows:
- Computer behaves strangely, i.e. in a way that you haven’t seen before.
- Programs take long time to load.
- Corrupts the system's data.
- Erases the files or programs from the system.
- Decreases the space in the main memory.
- Appearance of strange message or strange patterns on the screen.
- Slows down the system performance.
- Increase the size of executable files.
- Causes system to hang or freeze frequently.
- Formats the hard disk.
- Programs open automatically without getting instruction.
- Renames the files with different names.
- Missing of files or appearing of unexpected files.
- Displaying unusual error messages or encounters errors frequently.
- Unusual sounds or music played at random.
- Accessing of floppy disk drive or CD/DVD drives or flash drives occurs frequently without giving instructions.
- The personal firewall tells you that an application has tried to connect to the Internet (and it’s not a program that you ran).
- Your friends tell you that they have received e-mail messages from your address and you haven’t sent them anything.
- The system date and time may be changed.
