Here is what an upgraded Dell oem_slp system shows
Windows Product Key Information
Product Name: Windows 10 Home Insider Preview
Product ID: Removed for privacy
Installed Key: Removed for privacy
Original Key: Removed for privacy
Original Edition: Windows 7 HomePremium OEM:SLP
OEM Key: Windows 7 OEM marker present in firmware
On a clean install of windows 10 I don't think showkey can see the OEM marker. I think if windows 10 can see the OEM marker it should have no problems.
Dell forums has reported that you wouldn't need to change key to upgrade to windows 10 if you are using an OEM:SLP install.
I think there is going to be reverse issue. Those who have changed there key to what is on the back of the machine may not be able to activate windows 10. May have to make a phone call to activate windows 10. I am basing this on what I experienced in my testing.
The W.7 hacks slip in sideloaders with OEM SLP keys to fool Windows into thinking that it's an OEM SLP installation. People who use COA keys shouldn't be the problem at all.
ps: I have a clean Insider partition on laptop as well, and that install CANNOT see OEM info. Doesn't even know my vendor lol (at least in System Settings in CP/"About" in Settings).
Here is my story. I got a hold of the windows 7 retail version.
So, what I did is change the OEM install to windows 7 retail version and it activated & validate without any issue. Then I upgraded this to windows 10 10162. Even when Microsoft got the activation fixed, my system wouldn't activate. I think windows 10 got confused on what I had previously installed.
What I did is the reverse. I upgraded the Windows 7 oem_SLP and the pre-activation status remained before even signing up with a Microsoft Account. I keep the windows 7 retail on another partition.
As I said before in another post,
I haven't tried doing a clean install of windows 7 retail then upgrading to windows 10. That my next test.
I wanted to try the 32 bit iso version of windows 7 sp1. The oem key activated online without any issue. I could possible have some issue because the motherboad has been replaced under warranty. I am not worried about it since I switched backed to the 64 bit version of windows 7 oem_slp, I most likely will never need to use the key.The keys on the COA stickers are unique OEM keys. The way I understood it though is they aren't entered into the list on the Microsoft activation servers because they may never be used. It also forces you do a phone activation the first time you use it. This lets Microsoft verify you used it on the PC it shipped with. After that I think it just activates like normal on the next reinstall.
On the reply to me.
The windows 7 retail key when I changed the windows 7 oem to windows retail it activated & validated without any issues. When I upgraded the Windows 7 retail to windows 10 10162 preview it wouldn't activate even after switching to a Microsoft account and doing a verification. Do you know why it windows 10 wouldn't activate?
EDIT: I don't know why Windows 10 wouldn't activate?
Got a Dell Optiplex that had a fresh install of its Win 7 Pro using the COA.
Upgraded to win 10 10162 with no problem - activated automatically.
Showkey shows Original Edition correctly and has OEM:COA at end of line.
Also says OEM Key: Windows 7 OEM marker present in firmware.
So, no drama with this one (so far!).