No sound through PC speakers but headphones working - Acer Aspire 5336

i am using win7 ultimate. i am hearing very little or no sound via my PC speakers. however, i can hear sound via headphones.

checked all possible setting as per my knowledge. kindly someone help.

The point to note here is that sound is working perfectly OK in Ubuntu 11.10. so my speakers appear to be OK.

Are they both the same connecion? If the speakers are USB, see if you can find drivers on the manufacturing website.

Also in case you didnt.. Go to sound in the control panel double click the speakers you have (they should be there) and go to levels. Turn it up there.