You need a garage. As good as some of the people on here are, they can't diagnose a problem like that, from a second hand description. Anything that any of us come up with will be, to a large extent, guesswork.

For starters, I wouldn't even try starting it. If a timing belt/oil pump belt has failed, and you run the engine, it could be a wrecked engine job.

Thanks for the reply. I put an OBCDII diagnostic tool on it but it showed no codes. There is no more to tell really. Mum was using the spare key which she doesn't normally use and I read somewhere that a slight bend in a key can stop the starter from disengaging once started and therefore eventually burns out. That's what made me think starter