First type 192.168.0.1 into the internet url box. That's the local IP address of the router. It should take you to a router settings screen and prompt you for a username and address.
If it doesn't, then you have to reset the router, by pressing the reset button. The reset button is inside a small hole on the back of the router. You need something sharp like a paper clip, to press it in, and hold for 15 seconds.
Then wait for about a minute for all the lights to stop flashing and remain lit.
If you still cannot connect to the router now, then your network device on your PC is not configured properly, or you may have to go to Control Panel > Internet Options > Connections tab, and make sure it is set to 'Never Dial a Connection'.
My router needs reset every so often though, so that is probably the issue. Let me know how you get on..