Ethernet Cable Stops Working Why Did My Wireless Router Stop Working For Ethernet But Not Wireless?

Why did my wireless router stop working for ethernet but not wireless? - ethernet cable stops working

We used our wireless router (Linksys Wireless-G) by month for the wireless and Ethernet cable. Today, suddenly only works wirelessly. None of the four wired Ethernet ports are working. How can I fix this, and why did it happen? Thanks