How do I reinstall/install a router? My router used to work but it then just cuts off and doesn't work. My mate said something about when the modem was turned off it changed IP adress or something. I've been trying to fix it but to no avail. So how can I fix this problem?

Press and hold your router's reset button for a few seconds to restore factory settings. Then follow the manual

I can't find the manual.

what kind of router do you have. theres usually a button on the back of bottom that you can only depress with the pin or something, hold it in until the lights on the front start going crazy, it means its going through its reboot phase

It's a D-Link Wireless DI-524

Tried reseting it. Didn't do anything.

From what I can tell the computer will 'talk' to the modem and it will 'talk' to the router but it won't 'talk' to the modem through the router.