When you turn on the box, do you get video? Can you change channels using CH+ and CH-? Is there no Guide/VZ Software? If so, we can probably fix it. If you get NOTHING, not even TV Video, the box is toast.
If it's just a dead IMG, try this:
What happened is the VZ IMG got corrupted, so it dumps you straight into the Motorola Base Firmware until it can redownload the software.
Unplug power and coax. Make sure the coax jack is clean of debris and the cable is not damaged. Reconnect it after about 5 minutes and let it sit for about an hour. If it still doesn't work normally I'd say try it at another location where a known-good stb is located but it looks like both your boxes are dead. You could try connecting it straight to the Coax out of the ONT and see if that works. If it works there, you may have a bad coax run, if it's still dead after that, it could be a dead ONT. What lights does it have?
Yes it's possible for only one part of an ONT to die. I had one with a bad Internet portion, internet would randomly die, TV and Phone were fine. Sometimes it'd die once an hour, and I'd have to constantly reboot the ONT to get the internet back up. VZ kept insisting it was my router, after the 3rd replacement I demanded a tech come out and replace the ONT. He checked the ONT, and in less than 5 minutes went "Yep, ONT's fried". So don't always trust Verizon