I have tried the "apci" and "apm" options suggested without any luck. Even the "shutdown - ?" options.
I finally found a solution that works for me at https://bugs.launchpad.net/ubuntu/+sour ... +bug/43961. It appears that my Gateway 832 GM has an Intel HDA sound driver. I applied the suggestion as stated and I have been able to power down successfully using Linux Mint Elyssa and Linux Mint Felicia. See the quote from the bug forum that I used to resolve my problem.
Johan Holmquist wrote on 2008-10-23: (permalink)
Adding "rmmod snd_hda_intel" to the end of /etc/default/halt worked on my LG LW20 Express Laptop.
If you have the same kind of computer, just write this in a terminal window:
sudo gedit /etc/default/halt
enter your password (nothing will be shown, not even *, but it's still being written)
In the gedit window, add "rmmod snd_hda_intel" without the "" to the end of the last row.
'Shut down' and 'Hibernate' now works! Thanks StevenMcCoy for finding a solution and posting it here!
I hope that this will help those that have the same sound driver that I have.
To Clem and the Mint team - please keep up the excellent work on this project. I am 99% Windows free.