You have mentioned that in your previous O/S's you have used a direct connection, no issues at all. Is your Windows 7 experiencing issue on a wireless or a wired connection?
For now, see if turning off power-saving mode on the network adapters would help. You may do this from Device Manager
. Expand Network Adapters, right click on the problematic adapter, choose Properties, then Power Management Tab, uncheck the boxes.
Please post an update.