Opening powerpoint file problem

Hello,


I'm suddenly not able to open a powerpoint file I've been working on. It tries to open it, gets about four little bars into the open, then says "powerpoint can't open the type of file represented by xxx."
The file is a .ppt file, and says type powerpoint presentation. I'm not aware of any damage I did to it. I've tried renaming, and coping to another folder, no luck. I tried opening a new powerpoint file and them attempted to insert the slides, no luck, said wrong file type. Naturally this is an important file, not backed up (my daughter's highschool presentation due tomorrow for a critical grade). Any help would be appreciated. Ps, it opens in Word, just looks like heiroghliphics (sp?).
More info on the problem:
1.don't have powerpoint viewer, so didn't try this.
2. tried moving to a zip and to a floppy, still would not open.
3.do not have a mac to move to.
4. all done on PowerPoint 2003, no other version.

Any more suggestions are really welcome, thanks!