Office 2003 Lockups

Hi,
I have Office 2003 with all programs(Project, Visio,Excel, Powerpoint,Word Etc)
When I am on the Internet if I attempt to use Office the programs simply lock up until I leave the internet. This is driving me nut’s!
System Info
Athlon 2.2
Windows XP Media Center (All Up-Dates)
1.5 Gig Ram
100 Gig HD
Internet: Netzero via 56 K Modem
Avast