Dell Vostro 5470 stuck on logo screen, cant open BIOS

Hi there, Im pretty desperate right now. I was having problems booting from and USB drive on my Vostro 5470 and I tried to disable "secureboot" and enabled "Legacy" on the BIOS setup screen. Right now the notebook wont boot and wont open the BIOS setup either (Preparing to enter setup).

I tried disconnecting the Hard Drive, tried disconnecting the RAM, I tried disconnecting the BIOS battery and pressing the power button for a while...

Nothing will get me past the Dell logo screen.

What can I do to solve this? Please, help!