12.04 will not shut down.

[riverguy99]

Dell D-620 with 12.04. On proper shut-down procedure, computer acts like it's going to shut down, but then stops at the purple display with the "Ubuntu" logo and five dots. It will not shut down. I checked for some answers and was thrilled to find one that was said to have worked. It is:

1. sudo -i (to get a root shell, sudo gedit is not recommended)
2. gedit /etc/default/grub
3. Find the line: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
4. Change this to: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi=force"
5. Save the file and close the file.
6. Finally, in terminal: update-grub
7. exit (to end the root shell)

When I try item 5, "save the file," I can't because it comes up as a read-only file.
What am I doing wrong, or is there a step missing in the instructions?

[col48]

You should have permission to write to this file without sudo, but it may be you need root permission to run update-grub.
Check permissions with ls -l (both are lower case L) after cd /etc/default
On my system the permissions are -rw-r--r--
Between steps 1 and 2 do chmod 640 to get these permissions set.

[sikander3786]

Try:

sudo cp /etc/default/grub /etc/default/grub.backup
gksudo gedit /etc/default/grub

The first command there is to make a backup of your original file.

After making the changes:

sudo update-grub

Make sure you don't make un-necessary changes or you might not be able to boot.