I have a jumpdrive that apparently has been corrupted. I utilized Cnet download software to retrieve the files, however I cannot open the PowerPoint slides. The message that comes: No text converter for this file type--can you assist?

You may try this data recovery. I used to use it to recover my lost ppt filesafter. It works pretty well, you may give it a try.
Data Recovery - Recover Photos Songs Emails Videos and Data (http://www.recoverdatamac.com/data-recovery.html)

What is the file format of the files you have recovered?

Apply next solution to recover powerpoint slides with all the changes were made before corruption how to fix a damaged ppt file (http://www.fixdamagedpptfile.fixpptfile.com/)