Question : PowerPoint Issue

I have a PowerPoint that was saved in 2003 format.  It has been open several times without issue.  When I tried to open it today, I got the following error message:

"The selected file does not appear to be a valid Microsoft PowerPoint file. It might be another kind of Microsoft Office file or a file created by using a different product.
Try double-clicking the file in Windows Explorer to see if another program will open it. If PowerPoint opens again when you double-click the file in Windows Explorer, it is possible that the file is not actually a PowerPoint file but that it's extension was renamed to be that of a registered PowerPoint file type (.ppt, .pps, or .pot). To determine which program can open the file, try any of the following:
Contact the original author (if known) to find out which program was used to create this file. Then rename the file with the correct extension so that it can be opened by that program.
Try opening the file in other programs.
If you, or someone you know, are very knowledgeable about software, examine the file header in a text editor to determine which program can read the file.
Another possibility is that the file was damaged during transfer over a modem. If the file was transmitted over a modem, try re-transmitting the file.
Lastly, the file might have become corrupted. If you have a backup copy of the file, use it. It is not currently possible to reverse file corruption."

I tried to resave it but the Save As drop-down only gives me the option to save it as a 2007 PPT, not 2003.  When I did save it, another error message came up stating that the Converter failed (I have the fileconverter.exe from Microsoft downlaoded to my computer).  I have a feeling the file has been corrupted.

Answer : PowerPoint Issue

It does sound as though the file is corrupted.  Here is a document from MS on how to recover a corrupt PowerPoint file.  http://office.microsoft.com/en-us/powerpoint/HA011168781033.aspx

If those steps don't work, you may want to consider a third part PP recovery tool:
http://www.powerpointfilerecovery.com/
Or free versions:
http://www.freedownloadmanager.org/downloads/corrupt_powerpoint_repair_software/
Note that I have not personally used any of the recovery software, so cannot vouch for effectiveness.  As always, save a copy of the file as a backup before beginning procedures.