Frozen water pipes?

you start by turning water off to the whole house and heating up the house. I've never yet seen a case of frozen pipes inside the house [under the sink] unless there is a serious lack of heat in the house [usually none at all] and there is little or no insulation in the walls between the pipes and the outside.

The heater under the sink is your best bet unless you can come up with a way of getting some heat under your house. That's where the pipes are frozen. If you have a crawlspace and your pipes run along the underside of your house, that's where they're freezing.

Get some heat tape and wrap your pipes exposed to freezing temps...under ground pipes wont freeze...

The place pipes are going to freeze first is not underground. It's above ground. Find out where the supply line comes out of the ground. From there to where they go to the sink, shower, and toilet, that's where you need to get some heat. A hair dryer works just fine. You have to find the vulnerable spots, the place or places where the pipes don't stay warm, and heat those parts. When you heat the pipes, leave one faucet open part way. I suggest the kitchen sink. When the pipe thaws, you will hear water start running if it has anywhere to run to.