How to backup Windows 7 Home Premium from an HP pre-built to use on my new custom-built rig?

xxnick2dmaxx

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May 13, 2013
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So I currently have an HP pre-built PC with Windows 7 Home Premium 64-bit, and I just ordered all the parts to build my new PC, but didn't order a copy of Windows 7. Is there a way I can backup Windows 7 from my HP PC onto a DVD, flash drive, or External HD and install it onto my new rig? If so, where can I find my product-ids and such? Thanks, I'd rather not have to purchase a new copy of an OS I kinda already have.