If the tv resolution is different then right click on desktop>personalize>display settings and change the resolution. You may need to change the default audio device to the tv to hear sound through it.
I got an excellent picture on my TV, but when I disconnected from the TV, my picture on my laptop had a large black border on either side. I went to some setting and changed it from 'medium' to 'small' and that fixed it.
I never had a chance to fiddle with the audio settings. Do you believe the single cable will allow me to get sound on the tv?