Had another great InDesign experience this morning and have to share/post this tip for the search engine.
If you ever get a file that is missing the file extension, place this into InDesign. Go to the links palette and from the flyout menu choose "Link Information". You can then find the file format, add the 3dot extension and open in the program to edit.
In my case the came frommy old mac disks. I tried changing the extension to .jpg, .tif, .psd, .eps with no luck. Turned out teh file was a Scitex .sct file of which I forgot about.
This tip is not only helpful on the PC, but many mac people get files by email, where only teh data fork with the image data is there, but the resource fork identifying the file type is gone.