Not sure if people do this - but - if you are having trouble with your wifi - or pc - speed etc etc - try a reboot.
A simple process. Turn it ALL off at the power point- by ALL - I mean the whole kit and caboodle ! Let it settle for 5-10 minutes. Then turn on. You may be surprised at the result. The modem will reboot as will the rest. Most people generally never turn their systems off completely - at the plug.
If you have iPhones, iPads etc - connected by wifi - turn them off too - at the same time.
Not only may it help your system - you will also have 10 minutes of bliss - quiet.