My civic seems to have the yellow CEL light on when I try to start it up and it won't turn over. There were some wiring problems and I re-wired the deck and had power for the deck coming from the hazard lights... Dumb idea. I already tried to check the ecu error codes but nothing comes up when I connect the 2 wires in the green housing beneath the passenger side dash board. I'll be soldering the main relay soon and checking the spark plugs and fuel injectors. Any help will be greatly appreciated. Thanks in advance.

If it won't ever turn over, then there's either a problem with the starter, or with the wires coming from the ignition switch.

Check the FAQ about starter problems.

Also, if it won't turn over, that should be the first thing you have to fix, since if it's not turning over, it won't have a chance to inject gas or fire the mixture. So get it turning over first.

How did this start happening?

Well, a wire on the deck which supplies it with power even with the car turned off was either short-circuited or re-wired by the mechanic. I was planning on finding another source where electric may be supplied to the deck at all times so I figured that the hazard lights always had power supplied to it... It was a dumb idea since my car would crank but wouldn't start. I saw the other posts about how to check for ecu error codes but my cel light stays on and nothing blinks when the ignition is turned to "II". Thanks for all your help.