|The fact that the router did work and has stopped is indicative of a failure of the router.|
Click on my name above in my response and read my "how-to" guide titled "Troubleshooting Wireless Issues"
The same troubleshooting steps apply to any router as far as diagnosing possible router issues go.
If you go through the steps and it still doesn't work, then there's a good chance the router needs to be replaced.
The only other thing I can thing of, and it's something I would definitely try before replacing the router, is that it's not working because your provider restricts the MAC addresses that can connect. If this is doing it you can fix this by "spoofing" the MAC address of your computer onto your router.
First, find out your PC's MAC address. To do that, Open a command prompt window (ie: Start >> Run >> type cmd and hit Enter) and perform the following command:
What you're looking for is the "Physical Address" setting. It will look something like the following:
Physical Address. . . . . . . . . : 00-21-9B-27-22-A2
Once you have that, go into your router's management interface and look through all the settings. There will be one allowing you to "spoof" (ie: change) the WAN MAC address of the router. This is where you will enter the above MAC address.
NOTE: when changing the MAC address you must use a colon : instead of the dash - so it would look as follows:
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.