which plasma model? there'r many
720p or 1080p? ...fist if u plasma support 720p or 1080p your laptop or desktop need a video card that support such resolution. minimize everything, right click on the middle of the screen (make sure your tv is connected to the laptop or desktop) click on Screen Resolution....if u have these resolution available 1280x720 for 720p and 1920x1080 for 1080p then u can change it.....i hope this will help.