I tried to unplug for several hours and replugged them. Nothing! Where can I start?

You're going to need to go into a lot more detail, because no one can
Help if they have to guess what you're talking about.

If you're having a problem with a television, what is the brand and age of it?
What kind of problem are you trying to fix by unplugging it for several
Hours? If it is less than a year old and you bought it from a store, it
Should still be under warranty. Get the paperwork and user's manual,
If you still have them, and try calling the customer service number.

If it's not a TV, you may be using the wrong thread. Good luck.