1997 celica immobiliser and key fob help!, Car wont start.. Immobiliser? How to reset key fob? Options

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Hi All,
Background info: I bought a 97 Celica last year, bit of a doer-upper project. Came with 1 key with standard fob, fob has never worked. (I tried sticking a new battery in the it a while back but didn't work and never got around to looking into it further).

Anyhow step forwards to now, battery died a couple of weeks back. Replaced battery and car started up fine, great.. but went to start up again a couple of days later and no joy. Plenty of power still in battery, so I'm guessing this is an immobiliser issue of some kind? So, questions are:

- I'm assuming the model I'm driving does in fact HAVE an immobiliser. Is that correct??
- I've read stuff about the fobs and stock immobiliser, but honestly dont really understand it. Any knowledge on how its meant to work etc. would be appreciated.
- Is there a reset button or sequence of some kind I should have followed, or should follow now, to stop the immobiliser killing the car.
- Is there some way of testing the fob and getting it reconnected to the car.

I'd rate my knowledge of car electronics at about 1/10 so the more info anyone can give, the better.

Thanks!
A