Too little information here to give a reliable answer. If you aren't a skilled computer technician, you'll have to be very careful--it's quite easy to destroy a laptop by opening and disassembling it, even if it starts in perfect condition.
Where was the smoke coming from, anyway? The motherboard? The battery? The power supply? If it's something you can swap easily (for instance, the hard drive), try removing that and see if it will start.
In fact, if I were asked to look at a laptop that smoked out, I would remove everything removable: the hard drive, any optical drive, the power supply, all expansion cards, the battery. Now replace the battery and see if it will start. If not, remove the battery and replace the power supply, and try again. Does it start up?
If that doesn't work you'd need to open the case and inspect visually for fried components. Also, replacing the whole system is probably easier and cheaper than replacing the internal components of a modern laptop, unless you enjoy tinkering.