Computer Needs windows 10 product key

[Mark W]

Since I only use ccleaner to make changes to my computer I think it has done something with the windows 10 product key. I now have a watermark to "Activate Windows" on the display. I have tried to get into regedit to see  if I can find my product key but it comes up with I need to load the edge browser. Dont like edge browser and don't want to load it. Not sure how to get my product key back so I can put it back into the computer?

[nukecad]

There have been a number of posts recently on other fora about Windows 10 suddenly losing it's activation.

Nothing to do with CCleaner - particularly as those affected aren't using it.

It seems to be only OEM keys / manufacturers bulk keys that are getting deactivated and not retail keys, but that's not certain.
It appears to be either a bug in Windows, or Microsoft are tightening up on licencing and deactivating ones that they consider 'dodgy'.

Just for info you will have a product key stored digitally on your motherboard, but it may not be your current 'Windows Digital Entitlement'.
The Digital Entitlement is stored at Microsoft. And so can be deactivated remotely.
Obviously CCleaner can't touch anything on the MS servers, so can't have cleared that.

Has this machine always been Win10 or has it been upgraded from an earlier Windows?

I suggest that you head over to the bleepingcomputer forum and ask for help there, they already have a few of these lost activation threads. At the very least you'll get instructions/help on finding your Windows key and what type it is.

https://www.bleepingcomputer.com/forums/

PS. Your computer should continue to work fine even though not activated. There is the watermark, some customisation settings won't work but there are other way to customise than using those, and things like Onedrive and Microsoft Office may not work but non-Microsoft alternatives still do.

I have a Win10 laptop that has never been activated, it works just as well as my activated one.