Having startup issues with XPS 8930

I was surfing with Mozilla Firefox when when the screen froze, went black for several seconds, and then up came a blue screen telling me my computer needed to restart itself because of a critical error (possibly related to a Firefox update, the new feature called Off Main Thread Compositing). I let it restart but the screen went black again and didn't do anything for 20 minutes, so I did a hard reboot.

It now shows the following message:

Checking Media Presence....
Media Present....
Start PXE over IPV4.
Press ESC to abort PXE boot.

This message now appears every time I turn on my computer. It takes 1 min and 40 sec to get to the log-in screen.

Someone told me my computer was trying to boot from a network drive, instead of the internal drive. I went in to the BIOS, selected Load Defaults, and than saved and exited BIOS. This had no effect. I'm still getting the same message about PXE over IPV4.

I ran Dell Diagnostics (by pressing F12 at during startup). I got the following message:

ePSA 4306.25 Warning:
PCIe - Training error PCI tag 0100 Vendor ID-10DE Device ID-1F82 Svid-1028 SDid-1265 BUS 01: Link Degraded, maxWidth x16, negWidth x1, PCIe Slot 01
Yes No Retry

Someone told me to get a local technician to check to see if the video card was connected properly.

Is this ePSA message related to the PXE over IPV4 message?

My question: Is there anything else I can try myself before hiring someone to help?

NOTE: I had another bad startup issue in fall of 2021 (couldn't even get into the BIOS) and the local tech guy I hired had to wipe my drive and install an earlier version of Windows 10. Luckily, it updated itself properly, and I haven't had any problems until a few days ago.