This question was put back in 2008 from s.o. else but the response did not help:
When task switching back to Word 2003 or even after starting Word 2003 there is a delay of some 8 plus seconds.
No HD activity during that time, no network activity, enough memory ~2GB free, system is well guarded, no malicious software anticipated - checked for it often enough, no message pops up, ... just that hour glass delay and CPU load goes up to almost 100%.
Outlook, that uses Word as message editor, is delayed the same way when switching to a message being edited presently.
It has not always been that way, however, the incident that caused that behaviour cannot be conciously connected to any modification of my system, any individual or automatic update.