some of them might be an autosaved file. Look for files named ppt*.tmp (the * is usually 4 or 5 letters/numbers). Copy them to the desktop or another folder and then re-name them to change the TMP extension to a PPT extension. Double click to see if they are a copy of your file. If you're using Office 2002 or 2003, you can also try Start, Programs, Microsoft Office, Microsoft Office Tools, Microsoft Office Application Recovery to "Recover" Powerpoint (and hopefully recover the file), but I would copy those TMP files first!