After updating Avast! Free from 7.0.1426 to 7.0.1451 the black pop-up window appeared with a request to install SafeZone browser. (it was on full screen - that’s why I can’t make a screenshot).
When I click in the tray on the Avast! icon (orange ball), I see the message with a short description of this feature and the red cross (stop SafeZone). Clicking on the cross leads to the closing this window. But the window appears every 10 minutes.
I deleted avast! with avast! removal tool and installed the previous stable version (7.0.1426). But I have the same problem: SafeZone window appears again.
Operating system is Windows XP professional service pack 3 with automatic updates.
Some users also have the same problem.
Virus Scan shows no problems (Dr.Web CureIt, AVZ).
http://forum.avast.com/index.php?topic=100276.msg801406#msg801406
It will be corrected in a next program update soon. Sorry for the inconvenience.