Installing OS through USB, suggestions?

[Michael90CR]

I am stating my first build soon. I have a copy of Windows 7 from when I put a windows partition on the Hard Drive of the Family iMac, my plan was to use the disc copy to create an ISO image and install the OS through USB, however their is slight damage to the disc and I do not want to risk using it(if there is a major risk). I was wondering if there was anyway I can use the product key to get a downloaded copy of windows 7 to transfer on to the USB. If these fail, I heard that you can use a copy of the Windows 10 preview and then upgrade to the retail version when it comes out later this year is this true?

[Tycho]

Don't use windows 10 preview and I recommend that you do a fresh install. That's the best solution for your new system.

[Michael90CR]

Thanks for your advice: I used the chat function of the Microsoft support to get an ISO download link