I actually had this exact problem. For me, I had to manually reset my BIOS.
First, open up your computer and locate the CMOS battery (little coin cell battery connected to your motherboard). You can usually find this under your GPU, so you will likely have to unplug it.
Make sure all power is disconnected from the computer. Remove the CMOS battery and wait a minute or two. You can press the power button on the computer to make sure all power is flushed.
Once you've done that, put the CMOS battery back in. Reseat the GPU and plug the computer back in. When you power on the PC, the BIOS will be cleared of any custom settings you had.