Renault Clio 2000 not starting?

I have a 2000 Clio, which does not have central locking, or an electronic key fob. I've had no problems starting it up until today. There is plenty of power in the battery, but it never sounds like it's going to start. I've checked out the topics on immobilisers on here, but I don't think it is that, because the dash lights all look ok, according to the manual. Any ideas, please ?