Got a new SSD drive so disconnected the old HDD and installed 22.04 on the SSD. Everything went fine. Re-connected the HDD and mounted it so I could copy off some files. Still fine. Then I needed to run a program on the HDD so rebooted and attempted to boot from the HDD but grub came up with a message that there was no OS on the drive.
From BIOS I should be able to chose either drive, right? Any chance of recovery?
EDIT: I should have mentioned - the HDD had 22.04 on it that had been upgraded from about 17.x each time a new release came. It booted just fine before installing the new drive, and let me repeat that the HDD was disconnected while I did the SSD install, specifically so nothing would happen to it. After the SSD installed and loaded with 22.04, then I reattached the HDD and mounted it on a dir in HOME. So I am very puzzled why BIOS no longer sees it as a bootable drive