Laptops and notebooks are basicly the same thing. Netbooks however are not. Netbooks generally have Atom type CPU's and small HDD and not much RAM. Your system is a laptop/notebook.
Your Presario is both, they are actually the same thing! You probably mean Netbook. No it's not a netbook, a netbook is one of those tiny laptops with no Optical Drive (DC/DVD).
Agreed - they're both jargon for a portable computer. Also agreed that a netbook is different - categorized by lower performance, battery friendly and usually very inexpensive
Yeah, marketing people probably came up with the term "notebook" to make people think that a "notebook" is smaller and lighter than a "laptop" 10 or so years ago.