and....Laptop? It is quite hard to exchange the processor.
Since you are asking us about this, I do not think you have the ability to exchange the processor yourself, I would pay professionals to do the exchange for you.
celeron to i7 i'd just say no, whilst you might be lucky enough to have the same socket, and you might be lucky enough that it is not soldered, and you might be lucky enough to be able to buy a low power i7u processor, I doubt that the cooling mechanism would be sufficient.