Need help installing video card

HP Pavillion P7-1110, intel i-3, 8g ram, upgraded PSU to 430w, upgraded to latest win10 (v.1903), ACER SA-230 monitor.
I recently felt the need to install a video card to speed up slow re-draws in a CAD program. I don't game.

Bought a GIGABYTE GEOFORCE GT-1030 from Amazon. Draws it's power from the PCI-E 16 pin slot'
Power on fails and locks at HP's "press esc to enter setup". wtf?
So,duh..I read the min requirements and my PSU is under powered (the reason for the PSU upgrade)

Tried changing output of card from HDMI to DVI-D with same results.
OK..I got a bad card...returned to Amazon and got the same sent to me.
Again same results.
"F" this..went to BestBuy and bought a RADEON RX560.
Again same results.
googled..some say "disable existing video in device manager"...others say "don't do that, you'll lock yourself out forever"
My question is, if I enter safe mode, disable existing driver, shut down, install Radeon again and power up, end up with same results, pull Radeon and go back to what worked prior to all this rigamarole, will Windows automatically re-start the dis-abled existing driver?
Or will POST pass on to BIOS, which will then recognize the new card?
Or will I have a boat anchor?
In my attempts I've gotten to where I can see the P.O.S.T. results and feel that's where the computer stops.
I tried installing the driver from the installation CD first before physical card install but it stops as there isn't a card installed.Some help would be greatly appreciated.

Strange. Most desktop PC motherboards automatically switch to a discrete graphics card if one is installed.

What I would try is installing the graphics card, and then clearing the CMOS. Have you done that?

(I'd like to provide more detail, but HP's online documentation is fair to poor.)

Went to safe mode, devmgnt, dis-abled Intel (R) HD Graphics, shut down, replaced CMOS battery, installed GT-!030, re-boot, stuck on HP's welcome screen again. Beep code=video problem. Video card's fan spins up.
Using DVI-D out of card to HDMI input on monitor--no luck.
Using HDMI out of card to HDMI input on monitor--no luck
Shut down, remove card, re-boot, YAY---it's not a boat anchor.
Back to where I started with a good looking screen.

I'm at a loss. I was going to ask which PCI-E slot you installed the graphics card in, but I see that your motherboard has only one X16 slot.

I found this: Has anyone upgraded the graphics card on a HP Pavilion p7-1110? I tried but could not do it | Tom's Hardware Forum

Disappointing, if true. The latest BIOS update that I see for the Pavilion (HP uses one L) is from 2012. Access Denied If yours is older, you could try it, but I'm not optimistic. (The link is labelled Access Denied, but it works.)

I hadn't realized that you were working with an old machine.

Hi bob. Thanks a bunch for your effort. I spent hours searching and didn't come across that Tom's link.
Old man/old machine..LOL
Gonna take the Radeon card back to BestBuy and get my money back and search around for the GT 610 card and try that.
Since I have no need for 'wake on LAN' I'm gonna leave that BIOS update alone.

I do have a much more modern laptop that I could migrate the CAD program and all it's files to.
Or I could use more patience on the re-draws in this machine...