Volume control not working after I plug in speakers or headphones

When I turn on my 13 inch with Mac OS X version 10.6.8 or if I restart it, my volume works perfectly. However, whenever I plug in earphones or speakers the volume will be 'stuck' on the loudest it can go. When I use the volume controls on my keyboard or the slider at the top menu bar, it will make the clicking sound as if the volume is going up or down and will show the white speaker with the volume being adjusted but the volume will stay on the loudest possible setting. Even after I unplug my speakers/headphones the volume will continue to not work. There is no red light coming from the headphone jack and since it works upon startup, I'm inclined to think it's a software issue and not a hardware issue but then again, I don't know the first thing about computers. Since this has started, I've looked online for similar problems or suggestions but nobody has had this exact same issue, but I did follow the suggestions for similar issues. I repaired the disk (I could only do it for the Macintosh but I am running bootcamp with windows on the other side but I've used it maybe once for a pc only program and have never run the internet on it so I doubt the problem is coming from that side). It repaired a bunch of stuff but it didn't fix my issue. I also reset the PRAM and the NVRAM (I don't know what this does, but someone suggested it so I gave it a shot) and it did nothing. If you have a suggestion for something I can do, please be detailed, or point me to detailed instructions because my computer knowledge is very limited but I'm willing to work to fix this. Thank you!