I have HP and Dell laptops and desktops running windows 10 and 7. They were activated with OEM key when they were bought. The previous IT Officer has activated them again with KMS activation tool but i have the OEM product keys. If i re-install windows with a genuine windows 10 and 7 ISO from microsoft, will i be able to activate these computers with the OEM product key?
If keys are legit then Windows 10 will auto activate. Windows 7 iso won't download from the Microsoft site as it's OEM rather than retail. You'll need to find another site to download from. Why not create images using Macrium Reflect free so you can restore to an earlier image if things go wrong? Less hassle than a clean install.