Either in your preferred computer shop (physical or web) or at Microsoft: http://www.microsoft.com/windows/buy/default.aspx
Kees
I have recently switched over to iMac OS X Lion 10.7.3 desktop and my only problem is installing an updated version of PartyPoker (supported by Windows) which is an online gaming software prog. iMac supports only a beta version which is totally useless to me. I know I can do this thru Boot Camp which allows partitioning for Windows 7 and/or installing VMware Workstation. I would like to know if anyone out there has in fact installed Windows 7 using either of these two methods sucessfully and does PartyPoker work ok on the partitioned Windows 7. Also, 1) i can use only a legal Windows 7 installation disk...where can i purchase this and/or VMware Workstation 4.5 from? 2) which method is a better option..Boot Camp or VMware. Any assistance would be appreciated

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic