Meta-Troubleshooting Big Concept 2

So, you've done the detective work and have no leads. Now it's time to test & isolate the fault. First, think of what the quickest way to test if the thing is working or not, quicker the test the better because you may have to repeat this dozens of times. Check for loose connections, plug something else into the connections to test them. Reboot, reload, replace components. Check configurations & setups. Make a joke about hitting it with a hammer. If no power, check the fuse. Think about digging in and opening things up (will you void the warranty? Is there a warranty?)
Is there customer assistance you can call?

Get a price on a new one, consider if it's worth fixing.

Try searching Google with an exact model number and the word 'problem'. Fish around to see if anyone else has suffered through this before. Search for the product manual if you don't have one already.

Sleep on it, repeat these steps in the morning.