Your laptop should have display settings. Your TV manual should list the resolutions and frame rates supported on the HDMI and VGA ports. You need to set the display card to dual monitor mode with the HDMI port as the second monitor. Then set the HDMI out to recommended TV resolutions. The best quality resolution to use matches the TV native display resolution. The most commonly supported HDMI settings are 1920x1080i/29.97 or 1280x720p/59.94.
The Samsung HDTV will overscan unless set to "just scan" mode.
Blu-ray playback from a laptop will have special pass-through settings. See the manual.