Google/Gmail Chat Not Working

Hello.  I'm looking for some assistance with my mother's computer.  She's running Norton Internet Security 2011 (which was recently installed) and Internet Explorer 8.0.  She recently "lost" the ability to Chat within her Gmail account although she can still send emails.   I talked her through how to turn Chat back on, but it continuously just tries to connect without ever connecting.  I've logged into her account from my computer (which does not have Norton Internet Security installed on it) and I'm able to use her Chat feature so it's something specific to her computer.  Is this a setting within Norton Internet Security 2011 that we can modify so she can Chat again?  Thanks in advance for any assistance.