I had this very same issue this morning and found the power supply to be extremely hot. I replaced the power supply with an identical unit from another router, reset to factory defaults, reloaded my saved configuration file and was back in normal operation in less than 10 minutes. The power supply is an AF 1805-A, 5VDC, 2.5A switching supply and can be purchased from Amazon for $3.24 (as of today). Hopefully this will fix your problem as well.