1) Right click the Broadcom device in Device Manager and remove it (if it asks you to delete the driver software, click yes.)
2) From your laptop, go to your computer (or motherboard, if you build it) manufacturer's page and download the driver for the ethernet card.
3) Copy the downloaded EXE or ZIP file onto a flash drive or CD and then move it to your desktop
4) Run the EXE or the EXE inside the ZIP file and let it install the updated drivers.
5) Restart and provided I'm at least a little smart, it might work! If not, let me know and we'll try something else.