1) download latest drivers for any driver in your network section and modem section if your using a modem...but most are on broadband ethernet...
2) uninstall your driver or drivers to ethernet/wi-fi/modem- then reboot. (if you have experience getting into bio's turn off your network card before you uninstall reboot)
3) Get into bio's and turn on your network card if you did that then install new drivers. You may need to re-configure your connections with your network passwords.
4) unhook your cable box/modem from the wall for 30 seconds and ground out the cable copper tip briefly with a finger or something; unhook rehook all your connections; push your reset button for 10 seconds or unhook the power to the modem box breifly. rehook everything up.
5) physically disconnect and reconnect your network card in your computer box to reseat it.
6) about all you can do on your end as a computer user at home then you start replacing hardware or calling your ISP. you can call your ISP to ask them if in your area they are doing some work......you can wait it out for a little while before deciding you need new hardware.