If your toilet is clogged, you can typically unclog the pipes using a plunger. Simply press the plunger into place over the drain and move the plunger up and down rapidly to dislodge the clog.
Once you've unclogged the pipes, the toilet should drain itself.
If your sink or shower is clogged, you may be able to use a tool to unclog the drain. Many hardware stores sell hand augers and tools like Zip-its, which you can use to fish debris out of the drain. Please do not use chemicals on the drain, as these could damage your plumbing system.
If your heat or air conditioning isn't working properly, locate the central thermostat for your home and verify that all settings are accurate. You may be able to cycle the system off and back on again to restore the defaults.