Desperate situation

[Joentokyo]

I have been using Ubuntu 18.04 for quite a while. Today when I booted up my machine the downloads folder and music folder had disappeared. After spending much too long looking for a solution I decided to reinstall. Much to my surprise my internal dvd drive is no longer mounted and cannot be accessed for booting from my Ubuntu 18.04 DVD. I tried hooking up a usb cd/dvd, but even though I select it in BIOS the machine will not boot from it. The machine will only boot from the hard disk, so I am stuck with a broken version of Ubuntu 18.04. Anybody have any idea how I can put this back together?

[dino99]

First check the 'global settings' menu to see if the hardware is found and well identified. lshw can list them all too.
Then checking 'journalctl - b' or 'journalctl -b -1' will show you the main warnings (highlighted lines) and errors (red lines).
Is your installation encrypted ? Also check that blkid and fstab are matching.

[HermanAB]

Hmm, don't change anything until you know what is broken. Using a broken machine to try and fix itself, can make things worse, since it can make computational and read/write errors.

I would first try to boot off a USB widget. If that doesn't work, I would put the HDD into a USB caddy and examine it with another machine and make a backup.

[cmcanulty]

Have you tried Boot repair?

https://linuxconfig.org/ubuntu-boot-repair

[Joentokyo]

First check the 'global settings' menu to see if the hardware is found and well identified. lshw can list them all too.
Then checking 'journalctl - b' or 'journalctl -b -1' will show you the main warnings (highlighted lines) and errors (red lines).
Is your installation encrypted ? Also check that blkid and fstab are matching.

lshw showed the dvd drive is there, but it does not show up in the places menu or in home. Also, if I select it in BIOS to boot the computer, it is ignored.

I ran bleachbit the other day, but I cannot see why that would delete folders and settings.

[Joentokyo]

Have you tried Boot repair?

https://linuxconfig.org/ubuntu-boot-repair

Yes, but the problem is not booting the computer will boot as long as I choose the hard disk for it to boot from, but it will not boot from a dvd, which is what I need to do to reinstall the system. Also, the report given me by boot repair is way above my level of understanding of OS and computers.

[dragonfly41]

Also, the report given me by boot repair is way above my level of understanding of OS and computers.

Boot-repair provides a url during its run, which allows the report to be previewed by others here in this forum. Try again and post the url here.

[cmcanulty]

Also you can just try the recommended option on boot repair, usually fixes things

[HermanAB]

"I ran bleachbit the other day" - Bingo.

[1fallen]

"I ran bleachbit the other day" - Bingo.

+1 I noticed that also.
Bleachbit is a great tool with expericnce and without expericnce it can be your worst enemy.
I use it regulary but with a learned wisdom.