how to find out what the previous version was

I have a laptop that some tech who was not to good, upgraded this laptop to windows pro version and now I get the OS is not activated and need the key to activate error?
Dennis MillerAsked:
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JohnBusiness Consultant (Owner)Commented:
It depends on how long ago upgraded. After 30 days, traces of the old system normally vanish.
RaminTechnical AdvisorCommented:
Did you delete windows.old folder ?
If you didn't delete windows.old then you go to "\Windows.old\system32\" and open license.rtf file in a text editor and look at the 2nd title row, it will tell you the exact Windows edition.

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dbruntonQuid, Me Anxius Sum?  Illegitimi non carborundum.Commented:
Brand/model of laptop?
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Dennis MillerAuthor Commented:
I need to go back to the laptop and look it up. It is a Dell. That much I know and I am going to try to do what Ramin suggested as well. I may end up just getting the upgrade license and make my life easier. I am betting it was a home version. Next to find out how much or the cheapest way to get the upgrade license. The gentleman is a priest so I am trying to help. The last tech charged him for messing it up. I am trying to clean up his mess.
RaminTechnical AdvisorCommented:
If Windows.old is still there then you have also another option.

Download NirSoft’s ProduKey, run it on that computer and point ProduKey software at Windows.old .

Find the Download link at the Bottom of the page.
dbruntonQuid, Me Anxius Sum?  Illegitimi non carborundum.Commented:
>>  I need to go back to the laptop and look it up.

It is possible that the tech put on the wrong version of Windows 10 on this machine.

If this machine had Windows 7 or 8 on it then upgrade this way  I'm pretty certain your client would use at least one of those technologies.
Dennis MillerAuthor Commented:
It has been a rough few weeks but I am still alive. Thanks for the help.
RaminTechnical AdvisorCommented:
You're welcome and I'm glad we could help.
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