Outlook 2003 causing CPU usage surges

I have a problem with Outlook using my processor in big surges. I have a new Dell Inspiron 9400 with XP Pro. I have a firewall, Spyware Doctor, Registry mechanic, McAfee and have run them all to check for viruses and spyware. I also downloaded AdwareAlert. Technical support from Dell said it must be a virus. I can’t get an answer from Microsoft unless I pay them. They say it is Dell’s responsibility. I am stumped. I only have the problem when Outlook is running. Anyone else had this problem?