Go to your laptop manufacturer's website for the network drivers and any other drivers that are shown as missing in Device Manager (question mark symbol) - - all you need to know is your laptop model to get the correct drivers (provided that the manufacturer supports Windows 7 on that model).
Obviously to get the drivers you will need to use a PC that's already connected to the internet.
Download the drivers, copy them to a pen drive, then plug the pen drive in to your laptop to install them.