File Question on server

On Win2000 server I have a folder the stores an excel file that everyone shares, even though, after the file is opened, the second person can only open it as read only.

In that folder there are now many folders with names such as;
1c4b6b00
2cb01100
3o561100
52b7f200

I am assumming these are randon file names given when the excel file is opened read only? And if I am correct, should these not be temp files that are then closed when the user exits? What is the purpose of keeping these?

Thanks for any input you may be able to give!