First off, calm down and don't worry. Try resetting the microprocessor, I always do this first thing when I purchase a used receiver, someone might have changed all the assigned inputs. If not, as said above, ebay buyer protection will cover you if the item is not as described. I had an issue with the PS3 not liking the Marantz as well, try a different HDMI cable, it worked for me. One thing of note, the GUI won't work via HDMI, so you need to run an analog (I used composite) to view the GUI and change settings easier.
THANK you. I reset it, and its taking a few of the inputs now. Got it to show my PC screen, and a few of the analogs are working as well.
Sigh, sorry guys. I didnt know about the reset, and absolutely nothing was working before.
I'll keep you updated.