Powerpoint 2000 and WMF Temp Files

My boss creates powerpoint slide shows that contain around 50 slides with links to movies. When he opens the presentation it creates around 800 ms0*.wmf files in the temp folder. If the laptop crashes are the slide show crashes the files are not deleted. This all leads to other problems if he forgets to clean them out. Why are these files created in such a large number and is there any way to preclude this from happening in the first place.