Could you make sure that Windows Firewall is configured to let avast connect to the internet ? Any other security app running ? What other security app did you use before Avast ?
Hi,
You need to jump to XP Service pack 3 at least as there is many security issues. Use windows update to get it!.
Did you have any other antivirus on the computer before installing avast?.
If you used norton/ symantec or macafee, then you need to remove them compleatly with their removal tools.
Try a repair of avast trough add & remove programs.
Check for spyware using malware bytes free anti spyware test utility. See what that brings up.
I bet you have an infected system due to being on SP2