High defenition audio device installed and working but NO SOUND?

My computer has the sound driver installed but there isn't any sound coming out of my headphones or speakers! This has been going on for 2 days and i can't seem to fix it. I updated everything that windows 7 has to offer and still nothing!

Here is my computer:
Lenovo Think Centre
MT-M 8811-d1u
Windows 7 pro

Someone please help me! I need sound As soon as possible.

If you are using the front jack, test with the rear jack. It is easy to damage the jacks and the front one gets kicked and abused.

I can't remember the exact place but go to control panel and search for troubleshooting. In the results look for troubleshooting audio playback and let windows do its thing.

also, make sure the speakers you are using are set as default. Right-click over the little speaker icon on the taskbar, click playback devices, right click on the one you want to use and click make default.

First off check to make sure the volume is up on your monitor or t.v. If you have that hooked in to your computer. Next, check to make sure you have the jack in the right outlet, for speakers/headphones and not in the microphone or anything else. Check to make sure the speakers are hooked up and if a additional outlet for power for speakers is plugged in. Check your headphones to make sure they are not broken, wires torn anything. Make sure your speaker is turned on a red or green light is on them if portable. Go to your control panel and open look up hardware and sounds and look inside this and see if it is installed either your headphones or speakers. Look inside sound for any sound tests you can do, to hear the computer sounds.