Outlook 2003 Font change

We are running Windows 2003 in a citrix environment and have a user who’s email font change to times new roman 10pt when he sends html emails (outlook 2003), eventhough all options are set to arial 10pt – stationery, signature, mail set up, international fonts etc have all been looked at. Our helpdesk suggested deleting his account and recreating it in active directory then reattaching the mailbox. Can anyone suggest a less drastic measure or set of options we may have missed. Thanks?