Can't access BIOS!

I can't access the bios when I turn on my PC.

It says: Press <DEL> to access bios.

I spam-press <DEL> and nothing happens. I've also tried pressing all the f keys.

My keyboard has a BIOS switch, so I tried it with that set and it made no difference.

Hardware:

**Mobo:** MSI z170a G43 PLUS

**Keyboard:** Corsair k70