Antivirus working or not in your window

.Some time we have antivirus but we don't update.then some problem grow up in our system..if  your system were to somehow get infected with malware, one of the first things that malicious code does is to try and disable the anti-virus scanner. It may also attempt to modify the HOSTS file, so as to tamper with the anti-virus definition update process. Most popular modern-day anti-virus programs offer real-time protection against potentially malicious software and will throw up a prompt warning you.
now we go to start  antivirus chacking.
Launch Notepad on your computer
Copy and paste the following line into the Notepad file:

X5O!P%@AP[4\PZX54(P^)7CC)7}$EICAR-STANDARD-ANTIVIRUS-TEST-FILE!$H+H*

Save the file with a .com extension, e.g.  Avast tester.com. You will need to select All Files from Types at the bottom of the save dialog in Notepad in order to save the file as a .com file instead of a .txt file.

If the real-time protection mode of your anti-virus program is working properly, it should automatically trigger an alert, mean detect by avast.com file.if not detect with that file antivirus not working....