DavidR
2
Some information might not go amiss.
Can you be a little more detailed in the problem, are you saying there is no avast icon on the system tray, etc. ?
What Operating System are you using ? is it up to date ?
What avast! version home/pro 4.7.1001, etc. ?
Have (or did) you another AV installed in this system, if so what was it and how did you get rid of it ?