Getting OEM Product Key on Dell Inspiron N5010

Hello. The sticker under my device that contained my device’s key became unclear and i cant see the key. My laptop originally came with windows 7 but i was using 10. This morning i used the manufacturer’s tool to get back to the factory image (Windows 7). Now it shows that windows is activated and the Product id contains “OEM”. Is there anyway to get the actual key in the sticker that i can use to activate windows 10

isn’t there anyway to get it by even providing Service Tag?