Do a little test to your antivirus:
Open notepad, and copy the following text into it.
X5O!P%@AP[4\PZX54(P^)7CC)7}$EICAR-STANDARD-ANTIVIRUS-TEST-FILE!$H+H*
Save it as teste.com
If your antivirus assumes teste.com as a virus, it is working fine, otherwise change your antivirus.
(The file teste.com will not affect your computer. It just tests your antivirus application. This files exists in Panda Antivirus Website just to test it).