gimgiraffe :
xFeaRDom :
When the GPU is installed it should automatically change the choice.
Try booting into BIOS and finding where to change the graphics option from the Integrated Graphics to the GPU, cannot tell you how exactly but just search around.
You could always go into device manager, go into display adapters and disable the Intel(R) HD Graphics xxxx and it may swap to the GPU.
Saying that, is your monitor connected to the GPU or the motherboard? If it is connected to the GPU then it is working correctly.
I connected it to both the motherboard and GPU, should it be just the GPU or both? Thank you so much.
If it is connected via the GPU, and it boots with display, then it is using the graphics from the GPU, hence the on-board will be disabled.
Have you tried to do the following:
1 - Remove the power cable connected to the PSU.
2 - Press and hold the power button, to drain the power.
3 - Touch something metal to drain any static electricity you've built up, you can touch your case or anything that is metal.
4 - Remove the GPU
5 - Remove the CMOS battery and wait around 5 minutes, longer if you wish.
6 - Put the CMOS battery back in as well as the GPU - Connect the power cable and boot.
Let me know if this helps at all.