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What is the difference between a Laptop and a Netbook
Laptop/Notebook or Netbook?
Why would I buy a Netbook instead of a laptop?
If you want something which is easy to carry but allows you to connect to the internet, write the odd document or spreadsheet and have email access then you need a netbook.
If you want to store lots of files/data/music/video you could still go for the netbook with an external portable disk drive.
However if you need something more powerful which allows you to create CDs and DVDs as well as watch them without extra devices attached go for the laptop.