It doesn’t make sense that it isn’t working. As soon as you press the power you need to be hitting F2 and F12 repeatedly until you get something. Pretend you are rocking a drum solo between F2 and F12.
If it still doesn’t work, take a look at the keyboard. When you boot you typically see the numlock light come on confirming the keyboard has power. If you have a spare keyboard I would even consider swapping it out to see if you have better luck.