package linux-image-4.15.0-34-generic 4.15.0-34.37 failed to install/upgrade: installed linux-image-4.15.0-34-generic package pre-removal script subprocess returned error exit status 1

The bug occurred after I tried to read a plain and normal video DVD in my computer, opening it with the adequate software included in lubuntu OS. The disk got stuck in the machine, (it still is). I first saw a question mark on the dark screen, then after a while the ubuntu rescue screen, which I fortunately happened to use, and there I am...though being a total ninny as regards computers.
P. Toulouse
(ps: I wish I could get rid of the DVD out of the machine. The computer seems to work again)

ProblemType: Package
DistroRelease: Ubuntu 18.04
Package: linux-image-4.15.0-34-generic 4.15.0-34.37
ProcVersionSignature: Ubuntu 4.15.0-42.45-generic 4.15.18
Uname: Linux 4.15.0-42-generic x86_64
AlsaVersion: Advanced Linux Sound Architecture Driver Version k4.15.0-42-generic.
ApportVersion: 2.20.9-0ubuntu7.5
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: patrice 1031 F.... pulseaudio
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0x50440000 irq 28'
   Mixer name : 'SigmaTel STAC9221 A1'
   Components : 'HDA:83847680,106b0800,00103401'
   Controls : 28
   Simple ctrls : 10
Date: Sun Dec 30 14:37:44 2018
ErrorMessage: installed linux-image-4.15.0-34-generic package pre-removal script subprocess returned error exit status 1
HibernationDevice: RESUME=UUID=2286df02-fbeb-463f-8704-c69b8bffafce
InstallationDate: Installed on 2017-12-31 (363 days ago)
InstallationMedia: Lubuntu 17.10 "Artful Aardvark" - Release amd64 (20171017.1)
MachineType: Apple Inc. Macmini2,1
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-42-generic root=UUID=718326bf-43c5-4e39-afbd-8a4020cf6b76 ro quiet splash
PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No PulseAudio daemon running, or not running as session daemon.
Python3Details: /usr/bin/python3.6, Python 3.6.7, python3-minimal, 3.6.7-1~18.04
PythonDetails: /usr/bin/python2.7, Python 2.7.15rc1, python-minimal, 2.7.15~rc1-1
RelatedPackageVersions: grub-pc N/A
SourcePackage: linux
Title: package linux-image-4.15.0-34-generic 4.15.0-34.37 failed to install/upgrade: installed linux-image-4.15.0-34-generic package pre-removal script subprocess returned error exit status 1
UpgradeStatus: Upgraded to bionic on 2018-06-04 (209 days ago)
dmi.bios.date: 06/28/07
dmi.bios.vendor: Apple Inc.
dmi.bios.version: MM21.88Z.009A.B00.0706281359
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: Mac-F4208EAA
dmi.board.vendor: Apple Inc.
dmi.board.version: PVT
dmi.chassis.asset.tag: Asset Tag
dmi.chassis.type: 4
dmi.chassis.vendor: Apple Inc.
dmi.chassis.version: Mac-F4208EAA
dmi.modalias: dmi:bvnAppleInc.:bvrMM21.88Z.009A.B00.0706281359:bd06/28/07:svnAppleInc.:pnMacmini2,1:pvr1.0:rvnAppleInc.:rnMac-F4208EAA:rvrPVT:cvnAppleInc.:ct4:cvrMac-F4208EAA:
dmi.product.family: Napa Mac
dmi.product.name: Macmini2,1
dmi.product.version: 1.0
dmi.sys.vendor: Apple Inc.