New GTX 960 but monitor reads no signal

[y2ken]

You will choose/expand "Driver-Chipset (2)". Install both updates.

[y2ken]

#2  For example, if you use the wrong BIOS file, the BIOS file is corrupted, or the BIOS update is interrupted, such as a power failure occurring during the update, it can render your motherboard unusable [bricked].

#3 HP does not provide .rom BIOS updates, it uses .exe which is run from within a compatible version of Windows.

#7 BIOS will usually disable on-board graphics when an add-on graphics card is detected. That is likely why you are not seeing your onboard graphics. It is already disabled.

#8 Try disabling Secure Boot only. Don't enable Legacy support.  

Here is what @Jay_101 is referring to about clearing the Secure Boot Keys and receiving a Confirmation Code. Refer to Figure #4 of this HP support document "Computer Does not Start After Installing a Video Card"