When you say 'laptop', understand, there are some huge differences hardware/software-wise between them all. Why don't you take the time to provide more info about your hardware/software, including the HDTV? Be verbose. The more you leave out, the harder it is to get down into the nooks and crannies ;).
Also, tell us which settings/configurations you have tried w/ all equipment involved.
How can i connect my new home cinema Panasonic SC-PT170 EB-K with my laptop?
I tried with the HDMI, but not working. I tried connect the laptop with the tv, and tv with the sistem but not working.