connecting tv to pc

Go into windows appearance and set the resolution in the control panel for 1080
or better yet if you happen to have a decent graphics card use that devices control panel
 
i have radeon 6950 tried every setting in the amd catalyst control center, i am using a hdmi cable, the tv is 19ft from the computer i realise now that when i carry the tv and connect to vga that i use to connect my monitor every thing work ok but with the hmdi either black screen or no signal only 720x576 works