Ubuntu is the only OS installed on my Acer netbook. Few, if any, problems until, with no warning, it vanished from the boot list for the hard drive. I have been a ble to create a bootable USB to be ablee to use the netbook but have not been able to restore Ubuntu to the hard drive boot list.

As you can probabaly tell from the way the problem is described, I am a complete novice so any help you can give should assume no knowledge at all on my part and should be written as if for a simpleton.

Thank you.