more starting problems

hi all, new to the site, just after a bit of info and ideas.
i own a 1.8rt that has just died.

the problem started after the central locking sensor was leaked on through the arial.... common problem with renaults..... any way, driving down the road, the revs became irratic and died. the car would not start for about an hour. when it did start, it ran no problem for about 3 weeks until it died again. now running like a tractor, i limped it home, where as i idled the car, it dropped its revs and cut out. now it wont start at all. i thought it could be the fuel pump or starter, but i have checked both and they seem fine. im getting sparks at the plugs but no ignition?? :banghead:

today, tried it for a while and then bang!.... smoke and a bad metallic burning smell from the left of the engine. seems to have been the end of the starter motor! :uhoh:

does this sound like the cause? and how easy is it to replace the starter?
any advice would be greatly appriciated!
cheers.
stu.