406 will not turn engine over or start?

[BTFC]

Help needed please, I have a 1999 406 lx estate, my car fails to start, or turn the engine over. have a remote key that does not work any more , the push button fell out months ago, but the key works the doors fine and turns the ignition on ok, but a problem started 3 days ago, manually unlocked the car put the key in ignition, all the normal lights came on, but then when i tried to start the car there was nothing?? Did not even turn the engine over. I left it for a few hours while i went out then tried it again, It started fine !! I took it for a run, stopped at the shops, car would not start again?? kept trying it, after about 15 mins it started again. This morning it would not start, tried it an hour later it started, turned it off and it restarted again without any problems, tried it a third time and nothing again. Have left it all morning, tried again about an hour ago but no joy. Any ideas please??

[jasper5]

Starter motor?

[BTFC]

Starter motor?

Thanks for your reply, I guessed it was the starter, so have had that changed, everything was fine for a week, now i seem to have a dead battery?? Is there a correct way to replace the battery?? Do you know if there is a step by step guide on this forum anywhere? Might be a daft question?