Damn forgot about that one, sorry.
Bios don't usually freak out, so you were a victim of something rare, or not! XD
The thing, Bios/Uefi when you switch between GPUs (I mean Dedicated and IGP and vice-versa), sometimes and I never understood why, sometimes Bios gets stuck to one option, in your case, it was your IGP, since your dedicated didn't worked out.
By performing a Bios Reset, Bios is forced to perform a full run to check everything, and it actually managed to go search for your GPU and power it up.
You are far from the first guy that happened, this, altough, like I said, it usually happens when you switch between GPUs, the thing is, you did that, but only after you started to have problems, so for some reason you bios probably had some problem out of nowhere and you got that problem.
Anyway, I'm happy that everything is fine now.
I guess both of us learned something today.