The following are the symptoms of virus attack:

1. Your computer always stops responding when you try to use certain software. This could also take place due to corruption of an
essential file required by that software.
2. You received 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.
3. There is a double extension on an attachment that you recently opened, such as .jpg .vbs or .gif. exe.
4. An anti-virus program is disabled for no reason and it cannot be restarted. The computer may not allow re-installation of the
anti-virus.
5. Strange dialog boxes or message boxes appear on the screen.
6. Someone tells you that they have recently received e-mail messages from you containing infected attached files, and you are
sure you never sent any such mails.
7. New icons that you did not place on the Desktop appear, and are not associated with any recently installed programs.
8. Strange sounds or music plays from your speakers unexpectedly.
9. A program disappears from the computer, and you didn’t uninstall it.
10. Windows will not start because certain critical system files are missing, and you receive error messages listing those files.
11. The computer starts as expected some of the time, but atother times, stops responding before the desktop icons and
task bar appear.
12.The computer runs very slowly and it takes a long time to start.
13. Out-of-memory error messages appear, even though your computer has plenty of RAM.
14.New programs do not install properly.
15. Windows restarts unexpectedly.
16. Programs that used to run now stop responding frequently. If you try to remove and reinstall the software, the issue continues
to occur.
17. A partition completely disappears.