Is it a virus?

The last hours when i load the Google page and every one after that i recieve this message. Is this a glitch or a virus?

Please stick to your other topic on this subject, which I have answered.

I used Mozilla entire return to its own original settings it has by default by ussing some commands and finally the last command was Refresh Mozilla . Now i opened 3-4 pages and that Avast message has not apear. I will run some tests and see what will happen.

Good news, I hate mysteries also.