I have the same problem. There was a power cut and when the power returned, all LEDs on my d-link dir-615 blinked about 10 times then now all, but two, are stuck on. No holding down reset button and playing with power supply made any difference. They no longer blink but simply remain lit when power is supplied.
I see that, on another thread, a d-link rep (talking about another product) said, "if their switch looks more like a Christmas tree [then] it's beyond repair."
Mine looks very festive. Replacement is the only option, I fear.