If you’ve got a W7 COA sticker on your rig you can download a new ISO from microsoft. I’m assuming it’s a W7 pc.
My advice on this topic is still the same as I offered in the other recent thread. The OP of that thread rolled with the suggestion to purchase a particular used PC for under $200 shipped, then add a Samsung SSD. Total came to under $300 for a rather capable PC that included 8 GB ram, a W7 license, and a decent graphics card.