Perhaps the partition on the USB drive isn't flagged as a "boot" partition?Originally Posted by W1GUH
You could use GParted to check. It's usually under "System" , "Administration", and it may just be called "Partition Editor". If it isn't, it will have to be unmounted before you can change the properties of that partition.
I'll have to follow the sequence of events that resulted in your not being able to boot normally, Doug. I'll have to look at it a bit later when I have some time. This can be fixed!