Acer Veriton Z2640G - Manual (Page 67)

Internet and online security - 67
How do I know when my computer is at risk?
If the Action Center reports an alert, or if your computer behaves
erratically, crashes unexpectedly or if some of your programs do not
work correctly, your computer may be infected by malicious software.
However, do not blame every computer problem on a virus! If you
suspect your computer is infected, the first thing to do is update, if you
have not already done so, and run your antivirus and anti-spyware
software.