Since this is a Samsung TV and you have now posted into the Samsung forum I will lock this so you can concentrate on that one.
You may want to reply to your own post there and repeat the further information you gave here.
so my brother got a new cpu and gave me his old one. im trying to get this spare samsung led tv that i have to act as the monitor for the cpu but i cant get the display up despite connecting the vga cable.
i tried connecting my brother's previous monitor to the cpu and i couldnt get the display up as well. if anyone that knows whats wrong could help please