<human>: Can you summarize the given text in a few sentences?

Backstory:
I moved into my new house on July 24th and the previous tenant had a whole home entertainment system set up that my roommate and I purchased from him. It came with a projector, projector screen, and surround sound for $700, so it was a pretty good deal. Or so we thought. Today the projector made a popping sound and turned off. We were pretty peeved and assumed the lamp just needed to be replaced, so we ordered a new one. The lamp is still on its way and is expected to arrive Thursday, but from everything that I've researched, even if the lamp is broken on this projector it will still show the led lights on the control panel and on the "replace lamp" light. There are no lights on at all and no sound coming from the projector. We unmounted it from the ceiling and took the lamp out to look at it and it looks to be in pristine condition making us curious that the lamp itself is fine, and the power supply failed or the unit overheated. We are also allowing the previous tenant to store some of the stuff he didn't have time to move out in our attic and shed that he said he'll be back for in the winter.

My question:
What are we entitled to in terms of replacement of the projector from the previous tenant since we have only had it for about a month?
<bot>: My roommate and I bought a used projector, it broke about a month later, we're still in contact with the seller, what do we do?