Bought windows off ebay and the key worked, but Microsoft support said its invalid.

[spencermnemetz]

I'm refurbishing a HP Compaq 8300 computer for my dad. It had no hdd so I bought an ssd. The windows 7 coa wouldn't let me install windows 7 without buying an hp recovery package so I decided to just buy windows 10 OEM off ebay for $45. I installed windows 10 and activated windows but then I started worrying it wasnt a genuine copy of windows and might have viruses and other unwanted things. So I decided I would do a fresh install with a ISO i downloaded directly from Microsoft. But being an OEM key I knew I could only use it once. So I called Microsoft support to ask if I would be able to use the key again if I was just reinstalling windows. The lady told me the key was not valid and I should contact the manufacturer.
My question is if it wasnt valid, why did it activate windows and is there anyway to reinstall windows with that key?
Thanks

 

[USAFRet]

You can "maybe" reinstall, on that same system, with what you bought. But it might come back as not-genuine.

Just because it activates once does not always mean genuine.
The only way to know it is genuine is to buy it from a valid source. Some dude on ebay is not a valid source.

 

[ryder57]

I'm refurbishing a HP Compaq 8300 computer for my dad. It had no hdd so I bought an ssd. The windows 7 coa wouldn't let me install windows 7 without buying an hp recovery package so I decided to just buy windows 10 OEM off ebay for $45. I installed windows 10 and activated windows but then I started worrying it wasnt a genuine copy of windows and might have viruses and other unwanted things. So I decided I would do a fresh install with a ISO i downloaded directly from Microsoft. But being an OEM key I knew I could only use it once. So I called Microsoft support to ask if I would be able to use the key again if I was just reinstalling windows. The lady told me the key was not valid and I should contact the manufacturer.
My question is if it wasnt valid, why did it activate windows and is there anyway to reinstall windows with that key?
Thanks

I bought a "genuine " copy" of win 7 ultimate retail . Installed it , regestered it , 3 months later was informed by microsoft that it was a developers version and was not allowed to use it . They really wanted to know who sold it to me !
The point being it took 3 months after registering it for MS to let me know .