Hi,

I have a 1995 MX-5 that won't start. It isn't driven for months at a time but garaged and has very low mileage on it. Usually, I have to jumpstart it when I want to drive it and it works fine. This time, though, nothing. I even put in a new battery and it still won't start. I have an Audio Vox aftermarket alarm installed (came with the car when I bought it) and I thought this might be the problem. I disconnected it under the steering column (big black box with many wires). The car still won't start. In fact, it won't do anything (no radio, interior lights). A neighbor checked my fuses under the hood and said they were fine. He also checked the battery and said it was fine. Any other suggestions? Please help

Yes. You also need to check all under-dash fuses with a test light or multimeter. Here's how:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-46563-3.html#post252145

You may need to have someone who specializes in installing and removing aftermarket alarm systems come out to your house and make sure it has been fully removed.

I assume you have not crossed the terminals by installing backwards or having the wrong polarity battery.
Once this is up and running, may I suggest buying a "battery tender". Just hook it to your battery permanently and leave the plug in a convenient place. Just plug in and walk away for months without worries. A lot of boaters use this little charger. Seen them at Wal-Mart, and everywhere. I do this to my riding mower all winter, and my classic vehicle.

there are lots of possible causes why car won't start: No petrol, no fuel pressure, injectors not being fired, no ignition spark - it could be because of a bad ignition coil or bad rotor arms, or there is a dirty connections. it happened to my RX7 before, after checking all mazda rx7 parts (http://www.automotivemazparts.com/mazda-rx7-parts/) it turned out that my ignition module and starter are bad and needs a replacement. so better check yours.. by the way, have you done tune-ups lately?

Thank you all for your time and your suggestions. In the end, it was stupidly simple, so much so that I thought it wasn't possible. It was the master fuse. I would have looked there earlier but because this mechanic checked them and I saw him looking at them, I didn't double check. But after getting ripped off at the place I towed it to, (they called after a day later and said they had preliminarily looked at it and thought it would be something in the electrical wiring, then said it would be 500 dollars at least and wanted a deposit - needless to say I got a bad feeling and had it towed home), I decided to start from the beginning, inspecting the battery, checking that the alarm was thoroughly disconnected and looking at the fuses. It was so obvious that the fuse was blown - I saw it right away. I just can't believe that two mechanics didn't (or didn't want to) notice it. I got the part for 11 dollars and fixed it. The car started right up.
Anyway, my Miata and I are happily driving in the sun and I am reporting the mechanics of that shop to the better business bureau (and to Visa).
Thanks for all your help. It inspired me to get under the hood and fix my car. I am going to look into the battery tender. What an awesome website this is.