Word 2007 appears to hang

Word 2007 has worked without any problems for the last few months, but a few weeks ago this suddenly changed and I can't remember anything happening at that time. I can open a document and work on it, but as soon as I switch to another application and go back to Word again, it takes very long until I can proceed with work (at least about 15 seconds if not more). It also happens if I have opened two documents and want to switch from one to another. It doesn't depend on the size of the document, it might be even a blank page. I installed the Service Pack, ran all the updates, deleted the default template, but nothing changed. Any idea, how I can speed it up again?

Thank you,
Marcus

Problem solved. Somehow there was a problem in my profile (Word was the only application that had problems). I created a new user profile and after that it worked properly. It only took me some hours to have everything back as before, all my settings in the profile and so on
That was a real pain!!!