Not that you SHOULD
but you could try it
I could not really tell if you just uninstalled AVG or uninstalled- rebooted ran AVG removal tool > installed Avast
If you did not do the complete drill
(and you are not using zone alarm)
it's worth a try
First download the tools and make sure the Avast you have is the latest
uninstall Avast from add remove programs
reboot
run the Avast removal tool
reboot
run the AVG removal tool
reboot
If me I'd run the Antivir removal tool along the way- report if it finds anything- it's a registry cleaner optimized for old AV removal
remove any mention of AVAST in your Firewall - which is it?
now fresh install Avast
reboot
check the about avast tab in the blue ball for a couple of days and see if autoupdate is working
no big rush on this if manual updating is working
you could wait till next week and see if anyone agrees with me or has a better idea
BTW
you might want to remove avast from your firewall and make it re enable first- you might get lucky and would take a lot less time
do tell me if either of the hacks I proposed above work
no manual update for a couple of days- patience
toggle your firewall off
see if autoupdate runs
turn av back on again
thanks