Replacing Hard Drive with OS.?

My computer crashed so I bought a new hard drive. I also have a Windows 7 extension but I need a OS for it first. I understand it can be Windows XP/Vista/7? How do I do this without going to buy a $200 Operating system??



ThanksReplacing Hard Drive with OS.?
If you can't afford Windows there's always open source alternatives:



http://desktopbsd.net/



http://www.ubuntu.com/



http://www2.mandriva.com/



http://www.debian.org/Replacing Hard Drive with OS.?
http://www.ubuntu.com/



Ubuntu : D most user friendly Linux OS out there.