That’s pretty easy.
You need to order a Windows license under Dreamspark.
Download the ISO image that the Poseidon helpdesk has prepared (still pending.. it will be available as from September 1st) ou come to the Poseidon helpdesk.
Burn it, insert the DVD in your new laptop and boot on it.
If your laptop doen’t have a DVD drive you can find multiple way to install Windows on this page : windows.microsoft.com/en-US/windows7/installing-windows-7-on-a-netbook