toshiba satellite L455 audio issue

I hooked my Toshiba L455d (Windows 7) up to my TV (also a Toshiba) to use for DVDs, Netflix and internet access to TV (ABC/CBS/NBC.com). I used the correct monitor cable and audio cable. Everything works ... except ...
I can't turn the laptop speakers off when the sound is also going through the TV. The TV speakers are louder, but the laptop speakers are loud enough that you can hear them too.
There are two audio plugs on the front of the laptop. One is for headphones. This one doesn't work with the TV. No sound at all. Works with headphones though. According to the Toshiba manual this is OK and how it should work.
The other one is for external speakers and works with the TV. But the laptop speakers work at the same time--well actually with a fraction of second difference, giving an echo quality to the sound. Very odd.
If I mute the laptop it mutes the TV too. I tried going into the sound control window in Windows 7 and all the sliders control both the TV and laptop sound. Not to mention that they tend to go up and down at the same time.
Any thoughts?

Keith

 

A few quick corrections: the two jacks on the front are mic and headphones! That's why the one makes no sound--it's an input (mic) not an output. The headphones jack does make sound, just doesn't turn off the speakers. When you plug in the plug to the TV the computer asks what you just plugged in--headphones or a line out. If you chose headphones, the TV speakers don't work. If you choose line out then they do... but so do the PC speakers.

 

Aaach. Never mind. I got it to work by fiddling with the controls. It will work in headphone mode.