Deleted Files? I deleted all the files from the camera after I thought I had copied them to the computer. Turns out I have no sound! Is there a way to recover deleted files?

First things first: DO NOT take any more photos or videos with your digital camera (memory card) that you want to recover files from in case you may quite possibly ruin your chances of recovery.
Then here are some software programs that may help you out.
For Windows --> Data Recovery Tool
For Mac --> Mac Data Recovery
Here are the steps:
1. Connect your camera (memory card) PC or Mac which has installed the recovery program.
2. Scan for the lost files (photos, videos etc).
3. Recover them.

You may try some recovery software to rescue the files on your camrecorder, here are some for your option.

Photo Video Music Recovery (for Windows)
Photo Video Music Recovery for Mac

Both programs can also recover video and music files.

Note: Before your files are recovered, do not attempt to save more files to the camcorder in case the original files(your recordings) are overwritten.

Were the files saved to the camera's internal memory, or to an SD card? If to the SD card, then try using PHOTORECOVERY and have it scan the card and look for the files you wish to recover.
https://www.lc-tech.com/pc/photorecovery/

Time Machine would only help you in the future. Is your Mac set up with Time Machine? If so you should be able to get the deleted files that way. Click the Time Machine icon in the dock. Then go back to before you deleted the files, they are probably still available. f you don't have a Time Machine backup yet, then your best option would probably be uFlysoft Data Recovery for Mac
Mac Data Recovery Recover Lost Data with Ease

I know a firm which helps in hard disc data recovery. There are tools available but if you are unable to recover data from them then go to a firm of data recovery.
Data Recovery Manchester Data Recovery Services UK

Simply plunge this camera to your computer and download a data recovery freeware take a chance.
In fact, as long as you've not overwritten these deleted files on your camera, you do have chances to get them all back. What you need is only a third party data recovery program. You could easily get a number of data recovery freeware after searching over the internet.
Just try to restore your data back successfully:
http://blog4mark.blogspot.com/2012/12/deleted-files-recovery.html

Card Data Recovery is comprehensive data recovery software for any Digital Media that allows users to recover deleted and lost photos, music and video files from basic format to high-end raw image formats for most popular professional digital photo camera like Canon, Nikon, Sony, Olympus, Minolta, Fuji, Kodak, etc. which includes JPG,JPEG,TIF,TIFF,PNG,BMP,GIF,CRW,CR2,NEF,SR2,SRF,ORF,MRW. It also supports video & music formats including AVI, MOV, MPG, MP4, MP3, WAV, and more.

It has two versions separately for Window and Mac users. You can see its
official website here.

digital camera recovery for Windows (for Windows users)
digital camera recovery for Mac (for Mac users)