|If I'm understanding this correctly, you have two routers in your LAN. One connected to the internet and the other connected to the first router. Now the second router has stopped working correctly.|
Assuming I'm correct I'm going to suggest you click on my name above in this response and read my “how-to” guide titled, “Troubleshooting Wireless Issues” and go through the steps listed there. These steps work for any router really, I originally titled it "wireless" because I was addressing a wireless router issue.
If you go through the steps and it's still not working then you my have a broken router. If that's the case, I'm wondering if you really even need a router or if a small 4 or 5 ports switch (costing about $20 USD if you shop around) wouldn't do what you need. Unless you have a specific need for a second router (ie: you require a separate subnet) then you should probably just get a switch and save yourself some $$$.
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.