Guiri - If you are still within your return window, I suggest you return your Denon, as others have suggested, and try another brand. If passed it, then maybe sell on Craigslist.
Personally, I would recommend Yamaha and Pioneer over Onkyo in that price range. Newegg often has mid-level Pioneers on sale. Yamaha is usually less likely to find on sale. Onkyo is easy to find highly discounted. I prefer Yamaha and Pioneer from an audio perspective. But, Onkyo does tend to be feature-rich, most bang for the buck. And, they are all better than Sony.
