Do this first before you bring it to a mechanic?

Last summer I had 97 Accord which left on parking sport for couple days and did not start.

A Brazilian mechanic and tried to restart it, even spraying the brake cleaner in the air intake did not work and ruled out  timing belt need to be replaced. Later I just took off battery from my other car and replaced it and jump start and the car started with little hesitant.   Later I went to the auto zone and told them the situation and he answered me that the computer has something to do with it.

You may try this, first take the battery line off and do not leave the key on ignition. Try to jump start it. You may need to know if there is any key that needs to be readjustment , in my car it has tiny on off switch next to the hood latch.  (if you have any in your car , know it how it is and you may put it back as it was ).

Or you may ask your friend if you can check your car with his/her battery on your car just to start it.

If it is bitter cold and your car has low gas in the tank, it will be troubled to start. Advised to fill in gas if the temperature is below zero.

As you have 2006 civic and it would not be a starter problem because most starter would not go bad until 100k, if the you hear lauder  hissing sound but would not start it means your starter is good, may be you would like short video tape and bring it to AutoZone , they advise free of cost.

You may wanted to change the spark plugs , cost 2-5 dollars each , get platinum, last longer  and get the right one otherwise you will be facing second dilemma

They are the butcher.  Do not hurry to be butchered.