after finishing work in a document and then, trying to open an existing document in Word 2000 (operating system Windows 98) the blue toolbar at the very top of the screen flashes on and off.  the program is basically frozen and I have to ctrl+alt+del to exit the progarm.  when i go back into Word and open the document, there is no problem.  but if i want to open a second document, the toolbar flashes.  this just started happening within the last week or so.