Open a terminal and execute the following commands:
cd
rm .xprofile .xsessionrc
[ -d pterm ] || mkdir pterm
cd pterm
rm 10-autologonpterm.conf.txt xsessionrc.txt .myptermid countdown.py 2> /dev/null
rm power-button-off.png ptermlogo.png 2> /dev/null
wget http://www.giovanni.panozzo.it/guides/pterm/10-autologonpterm.conf.txt
wget http://www.giovanni.panozzo.it/guides/pterm/xprofile.txt
wget http://www.giovanni.panozzo.it/guides/pterm/ptermconman.txt
wget http://www.giovanni.panozzo.it/guides/pterm/ptermconfig.txt
wget http://www.giovanni.panozzo.it/guides/pterm/ptermlogo.png
wget http://www.giovanni.panozzo.it/guides/pterm/power-button-off.png
mv xprofile.txt ../.xprofile
mv ptermconman.txt ptermconman.py
mv ptermconfig.txt .config
chmod 755 ptermconman.py
And then (this requires to enter the uterm user password)
sudo mv 10-autologonpterm.conf.txt /etc/lightdm/lightdm.conf.d/10-autologonpterm.conf