2005 mazda 3i will not start at all. i assumed it was weak charge so i changed battery. i have accessory power. car will not start in neutral either. doesnt turn over. when i turn the key radio air and interior lights come on but car does not run. what could the problem be?

i have an update. i dont know if this changes the issue or not but the car has since started and drives fine. the AT light is on. (transmission?) as well as the engine light but as i said it drives fine and has started two days in a row since the no start. i had NO IDEA what is going on with this car. im not looking for "the answer" i just want an idea of what to expect when i take it to the mechanic. as it is i am a woman, and am sure someone will try to rpi me off. i just want to APPEAR to know what i am talking about when i go in. so any changes or still request this solenoid check? i have an update. i dont know if this changes the issue or not but the car has since started and drives fine. the AT light is on. (transmission?) as well as the engine light but as i said it drives fine and has started two days in a row since the no start. i had NO IDEA what is going on with this car. im not looking for "the answer" i just want an idea of what to expect when i take it to the mechanic. as it is i am a woman, and am sure someone will try to rpi me off. i just want to APPEAR to know what i am talking about when i go in. so any changes or still request this solenoid check?

I still think it's the solenoid. The solenoid has, when activated, a little arm that moves to activate the starter. That arm could have gotten stuck or frozen, keeping it from moving. I cannot explain why it freed itself ( think the Chaos Theory) nor can I predict when, or if, it will jam itself up again.
Now to address that light; There is a sensor in the Transmission ( tranny) that tells the computer when you are low on tranny fluid, providing you have an Automatic tranny which I believe, hence the A/T ( lol) . Have your fluid checked or check it yourself. You'll need to be parked on level ground for this. Open the hood and find the dipstick handle - it's usually bright yellow on a Honda, located close to the center of the engine compartment and could be either at the front, sort of next to the Radiator, or the middle driver's side, or the rear driver's side - look in your Owner's manual if you have it for the location.First block the wheels so the car won't roll off.
Start the engine and, with your foot on the brake, put it in Drive, wait 3 seconds, then reverse, wait 3 seconds, then neutral and, with the engine running and in neutral, pull that dipstick, wipe it off, re - insert fully, wait 2 seconds, pull again and read the level bu looking at the top end of the wetness on the stick and seeing if it is in the marked range. If no fluid present or not enough present ( below add mark) then go to your local auto parts store and ask for the proper type transmission fluid and top off using a skinny funnel, pouring through the dipstick tube.
If the fluid level is good then you may likely have a bad sensor and, depending on your financial situation, either get it replaced or just check your fluid every week.
I hope this helps and Merry Christmas!!!
Once again, thank you for using Fixya and I hope you are satisfied with our assistance. I still think it's the solenoid. The solenoid has, when activated, a little arm that moves to activate the starter. That arm could have gotten stuck or frozen, keeping it from moving. I cannot explain why it freed itself ( think the Chaos Theory) nor can I predict when, or if, it will jam itself up again. Now to address that light; There is a sensor in the Transmission ( tranny) that tells the computer when you are low on tranny fluid, providing you have an Automatic tranny which I believe, hence the A/T ( lol) . Have your fluid checked or check it yourself. You'll need to be parked on level ground for this. Open the hood and find the dipstick handle - it's usually bright yellow on a Honda, located close to the center of the engine compartment and could be either at the front, sort of next to the Radiator, or the middle driver's side, or the rear driver's side - look in your Owner's manual if you have it for the location.First block the wheels so the car won't roll off. Start the engine and, with your foot on the brake, put it in Drive, wait 3 seconds, then reverse, wait 3 seconds, then neutral and, with the engine running and in neutral, pull that dipstick, wipe it off, re - insert fully, wait 2 seconds, pull again and read the level bu looking at the top end of the wetness on the stick and seeing if it is in the marked range. If no fluid present or not enough present ( below add mark) then go to your local auto parts store and ask for the proper type transmission fluid and top off using a skinny funnel, pouring through the dipstick tube. If the fluid level is good then you may likely have a bad sensor and, depending on your financial situation, either get it replaced or just check your fluid every week. I hope this helps and Merry Christmas!!! Once again, thank you for using Fixya and I hope you are satisfied with our assistance.