Laptops in and of themselves are really limited when it comes to later upgrades, you can change the size of the hard drive, install a different optical drive, replace a worn out battery or AC power supply, and possibly add more memory after purchase. But when it comes to the idea of changing a processor or motherboard, it is basically impractical, very expensive, and not something most repair technicians would suggest doing. It isn't just a matter of openning the case, taking off a heatsink, lifting out the processor and installing a new one like you can in a desktop computer. Laptops are for the most part designed to be used the way they are built, and if you want a faster processor later, you will have to purchase a new laptop. I repair computers and laptops for a living, and I can assure you that if a customer asked me to change a processor in a laptop I would explain why it isn't practical or cost effective and suggest they consider purchasing a new laptop.
Can a celeron processor of a laptop be changed to a centrino or creo with the same laptop? And how?
Typically no. I don't know of a single laptop where this can happen.
Can a celeron processor of a laptop be changed to a centrino or creo with the same laptop? And how?
centrino really isnt a processor type, the centrino label is made for laptops with an intel processor, intel motherboard, wireless card, and chipset.