Boot to a LiveCD
Do a quick ls -l /dev/disk/by-uuid and note the UUID of your / and /boot partitions (the ones from your hard drive, not the LiveCD)
Mount your / partition to /mnt (if it’s encrypted you’ll have to look up the commands for this, as I don’t have them off the top of my head, but I believe LUKS is the usual suspect for encrypted disks in Linux)
You should now be in your Linux installation, though things may not be exactly as you normally have them
Check Grub to make sure it’s pointed at the right UUID (I also don’t have the commands to do this)
Sorry I’ve left so much of the heavy lifting to you, as far as finding the exact commands. I’m at work and have limited internet access. I don’t mean to come off as a “Well just RTFM,” jerk. But this should set you down the right path.
Also worth noting, I don’t know how much I believe that the UUID of your / or /boot partitions has changed. But my other theories are:
- Your / partition is just corrupted
- Grub isn’t configured to deal with an encrypted / partition
In going through the motions above, you’ll figure out if either of these are the case. And who knows, maybe the UUID(s) did change.