avast! Free updated .507 to .545 on XP Pro 32bit SP3
successful program update but no icon in system tray after reboot
started avast manually in Start-> (All) Programs, click avast, and icon appeared in sys tray
Restart and icon in sys tray this time
However subsequent boots avast was lagging at start with icon unstable, occasionally not starting
I saw that nvidia desktop control suite was activated - old hardware - so I disabled in Services
Still not quite right so I opened msconfig and there were three nvidia components checked for startup
I turned off these three components, parts of desktop control suite, and now everything is fine
The problem here, and to my mind you will often find this where you find XP, is that the hardware is dated - in this case an Intel850 server board - and likewise the associate software, while perhaps having been periodically updated, is not really up with the play - with avast5 necessarily being a new technology.
If possible, best to turn the antiquated stuffs off so they dont get in the way of the better running gear
This what I think is a lot of times where the problem occurs with computers running XP
what seemed like fancy features back may likely get in the way of a good running system nowdays