peugeot 306 td - lack of power black smoke peugeot 306 td - stu.rs

Hi all, Im new to honest john so please bare with me..I recently purchased a s reg 306 1.9 td sport. its been great the past few weeks apart form a bit of smoke in the mornings but this morning would not start i had to jump start it, since then the car has gone down hill to the point now where it has no power and spluttering the car will rev freely with a bit of smoke but will not drive. i have changed fuel filter and there does not seem to be any air getting in the diesel system. could this be a turbo problem or timing? thanks stu