I have a Creative SB Live! sound card and when ever i plug in my headphones i have to play with the headphone jack in order to make sound come out from both sides of the headphones.because if i plug the headphones fully in , sound only comes out of the right side.i was wondering, if i buy a new soundcard would the problem be solved?(the problem is not from the headphones since i've tried several pairs and all of them give me the same problem while if i try the same pairs on other computers, they work just fine).
There could be a problem with the sound card. Try to see if the connection to the MB is loose. Install then re install. If it fails, maybe it's time to get a new one.
