RE: Latitude E5470 Audio controller none in BIOS
When you say no audio controller in BIOS, are you referring to the Device Information section under System Information? If so, can you try entering the diagnostics (press and hold Fn whilst powering the system on) and running the speaker test? If there is no sound from that, it's not looking too good I'm afraid.
All I could then suggest is to try updating the BIOS:
Let us know how you get on.
Social Media Support
I'm based in the UK and I'm usually available Monday to Friday 10am-5pm GMT (BST)
Get Support on Twitter @DellCaresPro