How to recover the OEM windows version of my old laptop

chopper15

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Aug 12, 2011
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please I need help.

I Have an old laptop(Asus) which I bought 3 years ago which comes with win7 starter. so I bought an Ultimate version and removed the oem that was installed. Just a week ago I bought an MSI Laptop which comes with Windows 10 and I disliked it. So I'm planning to install my windows 7 Ultimate to my new laptop and Use the OEM windows version. But I didn't expect that I would need it so I didn't take down the license key. So my question is:

1. If i install the starter would it retain the old key automatically.
2. if not, is there a way to recover it.

so I beg anyone to help! I don't want to buy another win7 lest a pirated one.
I'm noob in this kind of thing.