Jenny,
Earlier you had a post that adding a Cname to your DNS records seemed to fix...which leads me to believe that not having an Autodiscover Cname may have also caused the freezing issue.
Other than the Autodiscover feature, mailbox size and not having all windows/microsoft updates are common reasons for Outlook 2007 freezing as well.
By chance are you also using Windows Vista? There is a known issue with indexing that can be fixed. Let me know if this is the case.
Hope this is useful
Masta7Mail
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