Excel Creates Temp File

I use Excel 2003 and within the last few weeks, it started creating a new temp file each time I saved the document. Each time I either do ctrl S or hit the save icon, it saves the file and creates a temp file at the same time. If I save the file 10 times, it creates 10 temp files. The only way to get rid of them is to manually delete them.

Please let me know if there is a setting which needs to be changed. I can't remember changing anything but I sure may have.

Thanks for your help.