When a virus infects your computer, it may have the following effects:

• The infected file may make copies of itself and take up all the free space on your hard disk.
• A copy of the infected file may be sent to all the contacts in your e-mail contact list.
• The virus may wipe clean your hard disk drive, deleting your files and programs.
• The virus may install hidden programs.
• The virus may open up a "back door" to your computer, allowing intruders to remotely access your computer or network.

The following symptoms are frequently caused by or associated with virus infection:

• 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.
• There is a double extension on an attachment that you recently opened, such as .jpg.vbs or .gif.exe.
• An antivirus program is disabled for no reason and it cannot be restarted.
• An antivirus program cannot be installed on the computer or your current antivirus program will not run.
• Strange dialog boxes or message boxes appear onscreen.
• Someone tells you that they have recently received e-mail messages from you containing attached files (especially with .exe, .bat, .scr , and .vbs extensions) that you did not send.
• New icons appear on the desktop that you did not put there, or are not associated with any recently installed programs.
• Strange sounds or music plays from the speakers unexpectedly.
• A program disappears from the computer, but you did not intentionally remove it.

A virus infection may also cause the following symptoms. Note: These symptoms may also be the result of problems in Windows that are not caused by a virus.

• Windows will not start at all, even though you have not made any system changes, and you have not installed or removed any programs.
• There is much modem activity. If you have an external modem, you may notice the lights blinking too much when the modem is not being used.
• Windows will not start because certain critical system files are missing, and then you receive an error message that lists the missing files.
• The computer sometimes starts as expected, but at other times it stops responding before the desktop icons and taskbar appear.
• The computer runs very slowly, and it takes a long time to start.
• You receive out-of-memory error messages even though your computer has a lot of RAM.
• New programs do not install correctly.
• Windows spontaneously restarts.
• Programs that used to run with no problems start to freeze up and stop responding frequently. If you try to remove and reinstall the software, the issues continue to occur.
• A disk utility such as Scandisk reports multiple serious disk errors.
• A partition disappears.
• You cannot start Windows Task Manager.
• Antivirus software indicates that a virus is present.