Next time you should list the computer model, it will help us a lots.
In theory, if the MB has pcie 2.0x16 slot, you had a good PSU that can handle the GPU, you should be fine. But you will consider other facts, like the case size, the MB BIOS version too.
So make sure the MB has the newer BIOS version.
Is it your pc, HP Compaq dc7900? If yes, what format? Small Form Factor or Minitower? Because it is the SFF, you have to buy the low profile GPU, and you can't buy the power GPU too, because the PSU is the lower wattage one, so check it (PSU) out.
And one more, what OS did you use? Win7 or Win 10. If you use win10 ( or win8) check the link it will help you if the PC will not boot with the non-OEM GPU.
http://nvidia.custhelp.com/app/answers/detail/a_id/3156/~/when-installing-an-after-market-graphics-card-into-a-certified-windows-8-pc