If, like me and seemingly many others, you've been having problems with Windows 7 randomly disconnecting your network while operating under heavy network load conditions, there is a solution.
It seems to be mainly with nVidia network adapters, but some other makes too. Just thought I'd post it incase
Open up your Network Connections folder. Open 'Properties' for the problem adapter. Click 'Configure' and select the 'Advanced' tab. Disable 'Receive Side Scaling' and the problem should be fixed