Can't boot my comp

[eliyahu22]

I had 16.04 on my comp, then I tried to install 18.04, and got an error message. I got out of there, and now when I try to boot I get the message "error: file '/boot/grub/i386-pc/normal.mod' not found
Entering rescue mode...
grub rescue>_

And that's as far as I get. Also when I put the usb stick with 18.04 on it in the comp, I get the same message. I tell him to boot from the usb stick; no difference.

What do I do now?

[yancek]

Was Ubuntu 16.04 the only OS you had on the computer?
What was the error message you got during the update?
Is your computer EFI capable?
Was 16.04 installed as an EFI install or Legacy?
Before trying to boot the usb, did you change the boot priority in the BIOS to set the usb first?

[eliyahu22]

Was Ubuntu 16.04 the only OS you had on the computer?

Yes, the only one.


What was the error message you got during the update?

Don't remember, can't get into it anymore.


Is your computer EFI capable?

Don't know what that is.


Was 16.04 installed as an EFI install or Legacy?

Don't know the difference.


Before trying to boot the usb, did you change the boot priority in the BIOS to set the usb first?

Yes I did, still doesn't want to boot.

[ajgreeny]

See Boot-Repair in my signature below and follow the instructions there to run the Boot-Info-Script. Do not run the default repair just yet but simply copy back here the pastebin link you get which will show us a lot more about your system.

[eliyahu22]

I downloaded the boot repair disk, put it on a usb stick, but I still don't get any further than before, he doesn't want to boot from it.