My last 2 computer buys did not come with a backup disc. SUPPOSEDLY the computer has a copy stored somewhere. I don't believe it, so I made my own backup discs - 2 sets, and I stored them in separate places, just in case 1 set got compromised.

Since you had the unit custom built, I would suggest you start by calling the builder and get their guidance on what to do and how to do it. They get this question all the time, they have info and offers. For instance, they may send you the set of discs for free or a small fee. They likely have a standard email they can send out to you, with step by step instructions, for your to make your own backups.

You already paid for a version of Windows. If you go to WalMart you are paying a second time, so that should be an option, but not your first option.