Blank screen + cursor after instelling new graphics card / Windows 10

BIOS i do not see how on support page or manual, each PC are different on how HP logo screen if shown will sometimes tell you, can be either Delete key, F8, F9,F10,F12 i am not sure. Thought you did disable the integrated card. I would not try changing the boot order then will not be able to boot. I would take out that bought card as a test and try booting just to see if it is faulty in any way and will be using the integrated card then.

Either a power issue, a faulty card or incompatibility with something if it works with the integrated card.

I did take out the add-on card and the computer booted without any problem. There must be a conflict somewhere.
And indeed, the integrated card is disabled in Device Manager.

Skippy said:

I did take out the add-on card and the computer booted without any problem. There must be a conflict somewhere.
And indeed, the integrated card is disabled in Device Manager.

O.k. well disabled in the device manager is not an issue, unable to get in BIOS and renable if it was disabled there for you would be then.
Chance your 300W power supply is not enough for card or the card is faulty or not compatible with the slot. Although should be backwards compatible with your PCI-E 16x slot. Just have to reinstall the driver for integrated and enable it