Sound didn't work, tried to fix it.... got Loud hissing sound instead

I've had trouble with my DELL XPS L502xX sound, it wouldn't work for: Web browsers and team speak, it worked for spotify, but now it doesn't work for anything, i tried looking for solutions, and i think i made it worse by following these step's that i probably should not have done:

 1. Open Device Manger and locate the device for which you want to roll back the driver. The XPS L501X has either Intel or nVidia graphics.
2. Right click on the device's name or icon and click on Properties. 
3. In the Properties window for the device, click the Driver tab.
4. On the Driver tab, click the Roll Back Driver button. (If it is disabled then there is not a previous driver to roll back to.) When the laptop is re-started, the old driver will be installed.


After i took those steps, i re-started the laptop, and the sound wouldn't work on anything at all... so i went to Control Panel > Device Manager > Sound, Video and Game Controllers 

and it said that Realtek High Definition Audio is disabled, so i enabled it and then this loud hissing sound started coming out from my headphones, so i tried unplugging my headphones and the sound was still there, so i disabled it, and now i don't know what to do.