Sceen lock is broken but I can't unlock it! How do I have an OS, or do I? I am perplexed!

I just attempted to re-partition my hard drive, not realizing that times have changed and that my uefi setup is different from my old mbr drive. So after re-partitioning and attempting to install a new OS, the whole thing failed; when I rebooted I got the message that my screenlock is broken and that I should login and run a loginctl unlock-session command. Ubuntu--the OS I thought had been wiped out by my reformatting attempt--is apparently still there but doesn't recognize the unlock command, but also isn't functioning because of a malformed entry in the iridium-browswer.list. I've been reading about gpt and understand that the partitions are different, but still don't understand how my partition table showed that my newly created partitions were (incorrectly) created yet at least some part of Ubuntu is still there.