my p5 won't start

[walight01]

i got a MIL and it said cat not getting hot enough, so we figured it was the o2 sensors. well since the first one is easy to get to i pulled it out, looked normal , blowed on it and replaced it back into the car, plugged it in and now the car won't start, my MIL went off, and according the the temp gauge, my engine should melt about now, i've tried disconnecting the battery and resetting the ecu but no luck, any ideas?
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[akhilleus]

make sure that the o2 sensor i sin right. U didnt touch it right?

 

[walight01]

i don't remember toching it, but will that ruin it? also if its not plugged in, the car won't start right?

 

[walight01]

i called mazda and they said its not the 02 sensor, the will run even with it not plugged in, does anyone have a way to test my ecu without having to pay 100 bucks at the dealership