menus in Outlook Express keep scrolling

I have a new Dell E310 with Windows XP Media Edition. When I use the customize toolbar menu and also when the the spell check "suggested word" list menu comes up in Outlook Express it keeps scrolling up and down really fast. I can barely catch the proper setting. :o) It seems to stop scrolling after a minute or so if I can make myself sit and wait ... patiently.  Does any one know what causes this bizarre behavior? Thanks for any help.