Ok, I have a strange problem with realtek onboard sound card. I bought PC parts and assembled it, installed Vista and latest sound driver from realtek.
At first when I plugged in speakers into the back or front panel audio jack there was no sound at all. Then after reading on some forums I disabled "front panel jack detection" in Realtek HD Audio Manager. After that sound appeared.

But if plug speakers to the front panel on my case sound comes out only from the right speaker, if I plug them into the rear jack, then sound comes out only from the left speaker.
If I plug headphones into any of the green audio jacks then the sound is too quiet to hear anything even if windows volume control is all the way up, so I have to use speakers to hear stuff because they have a volume control on them and can additionally amplify sound.
If I unplug the connector that connects case front panel jack to the motherboard then I can't get sound to work at all

Sometimes I have to crank the volume on the speakers all the way up because I can't hear anything. And my speakers are fine, I tried 2 different sets of them.

Do you know what I can do to make this work normal?

motherboard ASROCK A780LM
onboard audio: alc662
OS: Windows Vista

it seems you have a problem in the front's wire connector, maybe some wire doesn't make contact.

Then why if I unplug front wire connector from motherboard, back panel audio ports don't work at all

I don't know if these reference links might help in your situation, but they contain information on general sound card connection and setup issues.

See Connecting Audio & Sound Devices to your Desktop Computer by copying the link below into your browser. (for some reason the link doesn't work as an embedded link in a post)See Sound and Recording Tutorial