Macbook Air no longer recognizes external audio devices

Question

My Macbook air's audio port recently stopped recognizing external devices such as speakers and headphones.
The external devices are functional with other devices and fully plugged in, but only the internal speakers will produce sound.
This problem happened just recently with audio devices that had been working fine with the laptop before. I did not use any
audio devices that I haven't used with the computer before. They are fully plugged in, and I've already tried twisting the head
of the cord to see if it's going bad. The headphones I tried to use work fine with my iPhone.
I've tried opening System Preferences > Sound, to select the device, but it doesn't show up in the device list.
The internal speakers work fine, and continue to work even though the headphones or external speakers are plugged in, and in
the case of the external speakers, turned on.
Does anyone know if updating my audio driver would help?
Has anyone expirienced and resolved this problem or a similar problem?
Does anyone know how I can actually get in touch with someone who works at apple without having to go in to their store, as
I don't have time to do that and wouldn't be able to leave my laptop for repair since I use it for college?
Any help would be greatly appreciated!
Thanks so much!
Update:
I've tried using "Audio MIDI Setup", the external devices do not seem to be recognized by the computer.

Answer 1

Because something has gone wrong. I have no way of knowing what, and without backups, you're in a very bad situation.
If you want to preserve the data on the startup drive, and it's not already backed up, you must try to back up now, before you do anything else. It may or may not be possible. If you don't care about the data, you can skip this step.
There are several ways to back up a Mac that is not fully functional. You need an external hard drive to hold the backup data.
1. Start up from the Recovery partition, from Internet Recovery, or from a local Time Machine backup volume (option key at startup.) Launch Disk Utility and follow the instructions in this support article, under “Instructions for backing up to an external hard disk via Disk Utility.” The article refers to starting up from a DVD, but the procedure in Recovery mode is the same. You don't need a DVD if you're running OS X 10.7 or later.
2. If Method 1 fails because of disk errors, and no other Mac is available, then you may be able to salvage some of your files by copying them in the Finder. If you already have an external drive with OS X installed, start up from it. Otherwise, if you have Internet access, follow the instructions on this page to prepare the external drive and install OS X on it. You'll use the Recovery installer, rather than downloading it from the App Store.
3. If you have access to a working Mac, and both it and the non-working Mac have FireWire or Thunderbolt ports, start the non-working Mac in target disk mode. Use the working Mac to copy the data to another drive. This technique won't work with USB, Ethernet, Wi-Fi, or Bluetooth.
4. If the internal drive of the non-working Mac is user-replaceable, remove it and mount it in an external enclosure or drive dock. Use another Mac to copy the data.