Laptop shutting down repeatedly showing a bsod every time

My laptop imspiron 7520 se  is shutting down repeatedly on its own showing an error  message every time. Mostly it's showing error messages like driver irql not less or equal, system service exception, reference by pointer. It is running Windows 10..At first I thought it was due to drivers compatibility issues which many users of windows 10 have. I reset the pc but it was of no use. Finally I reinstalled windows 7 home premium which the laptop originally had, before upgrading to windows 10 but was surprised to see the similar problems coming again. I ran Dell diagnostics both in windows 10 and 7 and except for dvd drive, all other components passed test. Can anybody help?