Ebay is my job, send it back now! It's doa you you will get ALL your money back. Call ebay. 

Go to my ebay, click return this item, select not working, and wait for them to send a shipping label paid by them. If they squawk Ebay will extract ALL your money from their account and add it to yours. The shipper will scan the return label so they can't say they didn't get it. Ebay normally takes sides with the buyer, don't let them burn you! Don't try to get it working any more! No restocking fee!

But you will still have to wait for Dell to send it back to you, fixed or not. So that complicates the issue. You probably should have just gone directly back to the seller on eBay...

BTW: Was this PC sold as new, used or refurbished? If the Service Tag was previously registered to somebody else, you're going to need info about the original registered owner from the seller in order to do an Ownership Transfer to you so you'll get any remaining warranty coverage.

I didn't know he already sent it away, that would have been a slam dunk with no questions asked if he just sent it back. I have been selling steadily for 12 years on Ebay. They normally stand by the buyer which has hampered me a few times as a seller.

I read the original post too fast and missed the sent to Dell part but if he can get it back before the deadlines he will only be out the shipping to Dell fee. He needs to call Ebay which is easy to do.

Going to be messy, even if the PC comes back fixed from Dell. OP still going to need the previous owner's info to do an ownership transfer, and that assumes the eBay seller has that info.

If the eBay seller bought the PC from somebody else and is just reselling it, they may not have the original owner's info and/or may not be willing to provide it without getting permission from the original owner....

Like I said....MESSY!

The best thing would probably be to get it back from Dell without fixing it and return it to the seller for a FULL refund before the return deadline. Then he will be back to square one but much wiser. Transfers, receipts, owners info, etc. won't even enter the picture.

Bought from Dell on E-Bay, new computer

E-Bay seller was dell, new desktop.

No, it was not purchased direct from Dell on EBay.  Dell does NOT have an official sales channel on EBay (and I'd venture anyone representing themselves there as Dell is a very suspect vendor to be avoided). 

This whole thing sounds fishy, I would call Ebay to work with them and get that unit back to the seller ASAP.