Avast installation help

Norton trial automatically downloaded to my computer. Should I uninstall it before or after I install avast!?
Same question with windows firewall, should I uninstall before or after I install Zone-Alarm Free Firewall?

COMPLETELY uninstall Norton (special uninstall program
from Norton, I think) before you install Avast (2 AVs usually don’t
get along with each other). ZoneAlarm should be installed as
early as possible.

YES, run their removal tool (located here: http://us.norton.com/support/kb/web_view.jsp?wv_type=public_web&docurl=20080710133834EN&ln=en_US)

Installing Zone Alarm as early as possible allows you to say “Yes, allow” or “no, block” whenever you install a program, which makes things a bit easier in the long run.