dell inspiron 15R SE (7520-4729) - run for 1-2 seconds

Hello

I have laptop dell inspiron 15R SE (7520-4729)
I need key buttons sequenction which perform restore factory bios without no power (on disabled laptop).

Currently laptop, after pressing power button, running for 1-2 seconds and turning off, does not even show up "post" (dell logo

screen). It's my fault, i did too much changes in bios settings.

I already earlier used this key sequenction, to do that, but i forgot, so now i searching that again, but i can't find.

It was something like a:

"press tab button, left arrow, left arrow, right arrow, enter, right arrow etc.."

It's looking funny, but it works (I already did it early)

Please help me, thanks