Outlook 2003 – keeps freezing whilst browsing through emails

This has been happening since xmas on multiple computers.
My theory is microsoft updates have effected the email client.
When a user is browsing through their email,
the application will freeze for 2 minutes for no reason.
then resume back to normak and freeze, unfreeze etc.
problem is not related to personal folders either as i’ve tested this.

any solutions please, help?