I have five (5) computers wirelessly connected. Three (3) laptops and two (2) desktops. Two (2) of the laptops seem to work fine with the internet, but one (1) on the laptops and one (1) of the desktops often switch from local and internet connections to local only. I am using a D-Link wireless router and a Linksys extender. The network connections are at good to excellent. When the laptop and desktop with the issues do connect to the internet they lag. Our connection is DSL. I have disabled real time Windows Defender and am running MacAfee now. I have a strange file DQLWinService.EXE. I forgot to add the desktop uses Vista and is a new Dell (the one above Demensions).