Test this:
Open a terminal,
Press Ctrl+Alt+T
Run it:
sudo -i
apt-get autoremove
apt-get clean
UNUSCONF=$(dpkg -l|grep "^rc"|awk '{print $2}')
apt-get remove --purge $UNUSCONF
NEWKERNEL=$(uname -r|sed 's/-*[a-z]//g'|sed 's/-386//g')
ADDKERNEL="linux-(image|headers|ubuntu-modules|restricted-modules)"
METAKERNEL="linux-(image|headers|restricted-modules)-(generic|i386|server|common|rt|xen)"
UNUSKERNELS=$(dpkg -l|awk '{print $2}'|grep -E $ADDKERNEL |grep -vE $METAKERNEL|grep -v $NEWKERNEL)
apt-get remove --purge $UNUSKERNELS
update-manager -d
Software Updater will show up and search for the new release, after a few seconds, you will see a screen that saying:
However, Ubuntu 14.10 is available now.
Press the button Upgrade to start upgrading to Ubuntu 14.10.
The Software Updater will ask you to confirm still you want to upgrade, press Start Upgrade to begin installing Ubuntu 14.10.
Now, the Software Updater will prepare to start setting up new software channels, and after a few minutes, the software updater will notify you the details the number of packages are going to be removed, and number of packages are going to be installed, press Start upgrade to continue.