Help Getting Windows Without an Optical Drive

This is probably a stupid question but i'm going to building a pc soon and with cyber monday i'd like to see if i can get a copy of windows 8.1 but the problem is i can only find it in cd form and my new pc won't have an optical drive so i'd like to get it on a usb but i have no clue how so if someone could explain how to install it and link me to where i can buy it to put on a usb it would be much appreciated.

Thanks for the help.

after buying cd winodws 8,download the iso from the piratebay (not stealing if you use the product key you bought)

Really? I always thought there was a way to just download it with a key. I f thats the only way...

Hope this helpsĀ http://www.redmondpie.com/download-windows-8-iso-x86-x64-file-directly-from-microsoft/

Thanks

you can get it free, just gp to youtube and search how to activate windows 8 free and during the installation if windows asks for product key just click next

search on youtube, as you seem like a slight pirating noob