Test if your anti-virus is active?
If you are unsure whether your antivirus is active or not, there exist a tool detected by most anti-virus as a virus but however this software run a DOS program that only print a message to your screen as per below but depending on your anti-virus.
http://www.eicar.org/download/eicar_com.zip
However please take into account that if your anti-virus let you download the file and unzip same. This mean that your anti-virus has whether been disactivated or expired.