Hi, my name is ***** ***** I'm here to help you with this issue.
Have you tried Clearing and resetting the BIOS, instructions to do that can be found at the following link:
Please try it and let me know if you are able to enable your boot devices.
If you make changes do the changes stay?
I'm asking because it may be the that BIOS battery is dead.
Please let me know. Also, how old is the computer and what is the make and model?