Unable to Boot after BIOS change

My pc kept trying to boot to an external HDD used for backups (black screen after boot).  I tried to change the configuration to not boot from the Ext HDD and deleted a file. Now when it boots, it cannot find the OS and tries to boot in the PXE and I get a "No boot filename received" error msge.  This is followed by instructions to UEFI from Legacy.  When I do this, I get an error.

I believe that this pc had a Legacy BIOS when I first got it and I changed it to UEFI when I replaced the HDD.  

Is there a way to restore the UEFI settings?  I have tried to Load the UEFI Defaults and it still tries to boot in the PXE. 

I do have a backup and can do a full metal restore if needed. 

I also tried to use F12 and selected the HDD and it failed.  (Since the HDD is configured for UEFI, I am not surprised.)

I am just trying to figure out if there is something easier/simpler/less time consuming.

Any help would be appreciate.