Office/Excel Problem Can you help?

This is a weird problem. I have only seen this once before and do not remember the fix. One of my users opens up a 2007 document. It converts to 2003. During that process it changes the name to a bunch of random numbers i.e. xo0000000119 and automatically makes it a read only document while still saving/forcing a copy into temp files even though he hasn’t tried to save it yet….Help Please