Check other security programs settings on her computer. It’s very hard to tell from here, especaily 'cause we are unable to see how everything is set on her PC.

Also, check what firewall is installed on her computer and is everything set properly. Maybe some other e-mail notification program is “fighting” with Outlook Express.

Note: new avast! 4.5 uses new mail handling methods. Mail handling is completely transparent, in other words, she needs to set her e-mail accounts as if avast! doesn’t exist. Original pop3 and smtp server names, original loggin name and password given to her by her e-mail provider.