No sound devices

Hi, um i have read and tried virtually all the methods you have suggested to bring sound back but to no avail. one of my kids built me this computer and it was working fine at his house but now nothing. i am using a gigabyte S-series motherboard and have tried auto updates,the microsoft patch K8888something or other, admin tools and using the motherboard cd and reinstalling the realtek audio software. i really have lost all hope...please help and explain like im an idiot.
heaps and heaps of thanks

Welcome to Dev Shed.

1) Are speakers plugged into correct port on computer? If yes, continue to step 2. If not, correct problem 1 and then continue.
2) Verify speakers are plugged into wall outlet. If they are plugged in, or if you don't have speakers that require a wall outlet, continue to step 3. If it's not plugged in, plug them in and then continue.
3) Verify the power is turned on. If not, turn the power on and continue to step 4.
4) Open the volume properties by either:
a. Right-clicking the volume control in the system tray (located at the far right of your start-menu bar).
b. Start --> Control Panel --> Sounds and Audio --> Click the "Advanced" button halfway down the "Volume" tab
Then verify that "Mute" is not checked anywhere. If "Mute" is checked, uncheck it for all of the options. If it's not checked, continue to step 5.
5) Right-click "My Computer" and go to Properties. Click the "Hardware" Tab, then click "Device Manager" button. Are there any yellow exclamation marks? If not, is your sound card listed under "Sound, Video, and Game Controllers"?

Also some side questions:
1) I'm assuming you're using XP.. if not, please specify
2) These speakers do in fact work, right?

Hi thank you for replying so promptly.yes i have XP and i have researched like crazy and have tried everything from uninstall reinstall cmd prompts to remove hardware blah blah updates everything even tried 4 different speakers that all work fine in other computers.today i was on my seat for 5 hours and managed to uninstall windows media player but somehow installed realtek HD Audio manager and the 3D audio demo works!!!! sound actually comes out of the speakers.....but my computer still thinks that its got no audio devices.
i dont actually have a volume control icon on the task bar and have no other problems in the device manager category. the audio and game controllers are "working properly" and there are no ?s anywhere.
sorry i am still so desperate to fix this problem.... thank you immensely

Just because the volume icon is not in the system tray, doesn't mean it doesn't think there aren't any audio devices. Go to Control Panel --> Sound and Audio Devices --> Check the box that says "Place volume icon in the taskbar"

If you received sound from the demo, then it should be working fine.

Certain audio files may require certain codecs to get them to work, but overall it should be working.