Connecting to DVI monitor - no internet

[wallywattz]

I have an external monitor that I am trying to hook up to via the Mini DisplayPort to DVI adapter. When it's not hooked up, the internet works, but as soon as I plug in the monitor, the internet stops working. Any ideas as to why this is happening?

 

[wallywattz]

More information: It's a MacBook Pro. And when I hook it up, it still says I'm connected to my wireless network, but I just can't go anywhere on the internet. When I unplug the monitor, the internet works. Very weird.