What is a computer virus?
Symptoms of a computer virus
If you suspect or confirm that your computer is infected with a computer virus, obtain the current antivirus software. The following are some primary indicators that a computer may be infected:
- The computer runs slower than usual.
- The computer stops responding, or it locks up frequently.
- The computer crashes, and then it restarts every few minutes.
- The computer restarts on its own. Additionally, the computer does not run as usual.
- Applications on the computer do not work correctly.
- Disks or disk drives are inaccessible.
- You cannot print items correctly.
- You see unusual error messages.
- You see distorted menus and dialog boxes.
- There is a double extension on an attachment that you recently opened, such as a .jpg, .vbs, .gif, or .exe. extension.
- An antivirus program is disabled for no reason. Additionally, the antivirus program cannot be restarted.
- An antivirus program cannot be installed on the computer, or the antivirus program will not run.
- New icons appear on the desktop that you did not put there, or the icons are not associated with any recently installed programs.
- Strange sounds or music plays from the speakers unexpectedly.
- A program disappears from the computer even though you did not intentionally remove the program.
Symptoms of worms and trojan horse viruses in e-mail messages
When a computer virus infects e-mail messages or infects other files on a computer, you may notice the following symptoms:- The infected file may make copies of itself. This behavior may use up all the free space on the hard disk.
- A copy of the infected file may be sent to all the addresses in an e-mail address list.
- The computer virus may reformat the hard disk. This behavior will delete files and programs.
- The computer virus may install hidden programs, such as pirated software. This pirated software may then be distributed and sold from the computer.
- The computer virus may reduce security. This could enable intruders to remotely access the computer or the network.
- You receive an e-mail message that has a strange attachment. When you open the attachment, dialog boxes appear, or a sudden degradation in system performance occurs.
- Someone tells you that they have recently received e-mail messages from you that contained attached files that you did not send. The files that are attached to the e-mail messages have extensions such as .exe, .bat, .scr, and .vbs extensions.