How to disable auto-login:
WARNING: take extreme caution doing this or you will have a non-functioning netbook when rebooted. Be sure to read all instructions completely before making any changes and double check your work . You will need to remember the password you used when first turning on the Aspire One- good luck!
Edit the file /etc/rc.d/rc.S
Find and comment out the line
/usr/bin/xinit -- -br>/dev/null 2>&1 &