Check the specifications on the PCIe x16 slot on your computer. Some HPs are configured with the little known 25W "server" GPU spec. https://en.wikipedia.org/wiki/PCI_Express#Power
I've encountered this on Small desktops. Their intention is that business desktops run 2D graphics cards, so the 75W rating is not needed.
Also look into whether BIOS is AHCI, or newer EUFI. The GPU BIOS must match. GTX 750s come both ways.
I think only msi version of gtx 750 have dual bios ,, i can't find it,,
my bios is legacy version,, hp locked it .and there is no return policy if i wanted to try the
card any way.
My PNY GTX750 was legacy, MSI is known EUFI card. I haven't seen dual BIOS GTX750, but then I didn't need to look. Sapphire does dual BIOS, my R9-285 has it. But it has video conflict with Dell BIOS so I can't recommend it. Newegg has good return policies. I haven't had to try it though.