You shouldn't need and disc anyway. As ethel says, reset the router (small hidden button at the bottom of the router).
With both your computer and router turned off, connect them up with an ethernet cable, and turn both on. Once loaded do as ethel said and open internet explorer and type in the address bar "192.168.1.1" (no quotes), and it should load your router page. From there you should input your ISP username and password, as well as change the router's SSID (name) to something familiar to you.
If you goto philips.co.uk/support, you can find your router model and get the user manual, which will explain in more detail.