How to install windows 7

Basicly, I want to do a build like this 

 

http://pcpartpicker.com/p/jfMDhM

 

But, I'm not sure if the case will allow me to put an optical drive in it, if it doesnt, then how does one load windows on a flash drive and transfer it to a build with no OS. Help plz

You can use a few methods. If you already have the Windows 7 disk, use another PC to create an ISO image of the disk. You can use ImgBurn - it's free and clean and could not be easier to use. go to www.ninite.com and select it from the program list and download a malware free version.
Once you have made the image use  http://www.isotousb.com/ to write the ISO to a USB flash drive and make it bootable.

Then all you need to do is build the PC and use a flash drive to boot instead of a DVD and walla. Optical drive is now obsolete, and you save $20.

Hope this helps.

Yay. Thx. just wanted some info on this. Also...

is their any way to get windows for free or something

That's a question for a different forum.  if you want a free easy to use OS use get Ubuntu you can also get steam and download some game too

There is a guy selling Windows keys on here for like $10. He and the keys are legit. 

get windows 8 and then wait for windows 10 and then upgrade