Viewing and Transfering files between Nexus 7 (13) and Win 7sp1 x64
Follow this answer to access Android Devices' files over a PC. 
https://android.stackexchange.com/a/42703/21342

You don't have to download any other application to start an FTP Server on your device, simply go to Remote Manager in Tools and press Start.

Make sure that both the phone and PC are on the same network.