Sound stopped working.

I'm not sure why and what the cause of it was, but my sound has stopped working. Also I didn't know which sub forum to post this in, so sorry if it's in the wrong place.

Plausible causes
-I can't narrow down to a specific time where the sound stopped working due to bad memory
-It may have been after a regular shutdown, where I shutdown the computer normally first and then turned off the power switch on the back because i was moving some power outlet expanders around.
-I had not installed any crazy software or physically touched my pc (other than the on and off button/switch) before the sound stopped working.

Problems
-Sound not working for any devices that go into those analog or i/o sound ports. (The pink and green ones). Both the front and back panels don't work.
-USB may be working. ( I have a usb camera with mic, and it seems to be picking up sound. I can tell because the sound loudness changes along with how loud I am, so it seems to be working, but I can't tell for sure since I can't hear the playback.
-My regular mic (pink port) isn't working either, since the loudness of the sound does not change with my loudness, when I am testing the sounds.
-When I plug my speakers or headphones in, and turn the volume up I can sometimes hear a very screechy noise, that's not the default static noise feedback that I get when I turn up the speakers with no sounds playing. Sometimes I hear no noise at all. When I try to play music or other sounds, it creates low quick thumping noise.
-The computer does recognize when I plug my sound devices in, what sound devices I have plugged in, and what port they are plugged into.

My motherboard (that I'm pretty sure has integrated sound)
-Gigabyte H55M-S2V

Things I've done
- Made sure that it wasn't the audio devices that weren't functioning, but the computer itself, by using both my mic and my speakers with my xbox.
- Uninstalled and reinstalled the realtek audio drivers
- Fiddled with the realtek software and windows audio controls to try to get sound to work. (I have literarly tried about every single different option, I am positive that the problem does not lie within the software, as the same software setup was making the sound work before)

Things I haven't done
- Open up tower to check for physical problems

Help would be greatly appreciated,
Thanks in advance.