No power light on cable box. How do I get a new one without going to the store which is pretty far away?

Have you already tried unplugging it for 1 min then reattach the power cord?
That would force the box to do a system refresh.  
If the above does not work then it likely the box is fried and needs to be replaced which you can do by calling Xfinity technical support. 
They will send you a replacement box but the old one will have to be returned usually by you at a store. 
Since you store is card away you should try to request being able to ship it back as prepaid by Xfinity. 
Good luck. 

@Gene621 Good afternoon! Thank you for reaching out to our Community Forums Team for assistance with your TV box. I'm sorry to hear you are running into some difficulties with your box, but I can assure you, you are in great hands! If you log in to your Xfinity My Account, you can order a new one from there, I can also assist you in getting a replacement box order. If you prefer assistance I would be delighted to assist you in getting a new box order. To begin, can you please send a Direct Message with your name and service address? 

To send a "Peer to peer" message:
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• Click the "New message" (pencil and paper) icon
• Type "Xfinity Support" in the "To:" line and select "Xfinity Support" from the drop-down list which appears. The "Xfinity Support" graphic replaces the "To:" line
• Type your message in the text area near the bottom of the window
• Press Enter to send it