How does a netbook differ from a laptop computer?

There is no "difference" in that a netbook is a type of personal computer. A netbook differs from a desktop computer in that it is designed to be portable. They differ from laptops and notebooks primarily in size and processing power (netbooks being smaller and less powerful).

PC and notebook are pretty much interchangeable. They are a more normal computer as such. PC's and notebooks nowadays have pretty much the same capability as a regular PC, with similar processors, similar capacities of memory and disk space and integrated optical drive.

The main disadvantage of a PC and Netbook is that the Netbooks are portable however PC's are not.

Intel atom based processors Netbook is a great little piece of technology, lightweight and easy to take anywhere.