I had the same problem. At first the charging light wouldn't go on. Then some time later after trying again it did go on, but went off again after several minutes. Later it went on and stayed on, but it never changed color and I still couldn't turn the phone on.
Finally I sent my phone in for repair under warranty and they did a board swap without charging me anything. I had cyanogenmod installed, but they may not have known that if they weren't able to turn it on either.
Now my phone is working again, so I'm happy.