I recently had my Dell Inspiron 3542 crash. My issue is that it came with Windows 7. However, the recovery disk that came with the computer is for Windows 8.1. I researched a bit and found that I could create a recovery disk through Dell by using my service tag. I did this on a USB on my other computer and reinstalled Windows 7. Now I am getting the pop up saying my OS is not genuine. I have no key for this and the sticker on the computer is also Windows 8.1. Please help.
If the sticker is for Windows 8 then it should not have Windows 7 preinstalled... It makes sense that you get a non-genuine install.
The only scenario possible is Windows 8.1 Pro with downgrade rights to Windows 7 Pro. The Pro edition is rarely preinstalled on an Inspiron which is a home model.
When looking through the system configuration via the service tag, it shows:
Windows Blue = Windows 8.1
P = Pro
Looks like your system shipped with Windows 8.1 Pro with Downgrade rights to Windows 7 Pro.
I advise clean installing Windows 10 Pro directly. Windows 10 TH2 installation media will automatically pick up the Windows 8.1 Pro from the UEFI BIOS and activate when online.