Another pain point that I found a quick solution for. I thoroughly enjoy my specced out MacBook Pro, but sometimes I still must run Windows for things like 3D CAD with SolidWorks. For this I use a free virtual machine tool called VirtualBox and run Windows 7 seamlessly and flawlessly.
However, occasionally I’ve had trouble connecting to the internet in Windows (the guest). I searched around for almost an hour, and found a quick solution that takes less that 5 seconds. (seems to be a trend, no?)
While running your guest OS, in my case Windows, go to the VirtualBox menu at the bottom and click on “Devices -> Network Adapters”.
Choose “Attached to: -> NAT”