Install on new computer (old download)

[jimn]

6-8 months ago I downloaded Avast!4. After some time I licensed for 3 copies for 3 years.
I had only 2 PCs at that time.
Today, on a new PC (XP Pro SP2 with latest downloads), I copied the download to it and ran the setup.
While it seemed to work, I got no icon in systray and XP reports no virus scan active.
I did manage to get my license into the thing (I think).

What do I need to do to get this running on the new PC?
Thanks

[jimn]

Please ignore...

I had rebooted several times with no joy, but a reboot after entering the KEY put all back to expected/wanted.

SORRY to have bothered.