Can not get 3 speakers on my samsung home theater to work!

There are a few settings that will just give you a stereo output. The first one is with the Pro Logic II. If you press the PLII Mode button on the remote it will go through a series of settings from MUSIC ➞ CINEMA ➞ PRO LOGIC ➞ MATRIX ➞STEREO ➞ MUSIC. Pro Logic setting will only produce sound from the front speakers and Stereo from the front speakers and the sub. Put it on Matrix for 5.1 surround sound.
Also for speaker settings follow the instructions below.
Signal outputs and frequency responses from the speakers will automatically be adjusted according to your speaker configuration and whether certain speakers are used or not.
In Stop mode, press the MENU button.
Press the Cursor down button to move to Audio and then press the ENTER button.
In the SPEAKER SETUP, press the ENTER button again.
Press the Cursor button to move to the desired speaker and then press the ENTER button.
For C, SL, and SR, each time the button is pressed, the mode switches alternately as follows : SMALL ➞ NONE.
For L and R, the mode is set to SMALL.
SMALL : Select this when using the speakers.
NONE : Select this when no speaker is connected.
Press the RETURN button to return to the previous level.
Press the EXIT button to exit the setup screen.
It also seems that with this system, if you are on 5.1 surround but your music source is only in stereo, you will only hear stereo.