i am atempting to connect my telly to my pc via a hdmi cable but it is not working the hdmi port is on the motherboard but i also have a ati radeon hd4800 card and i am thinking the the card is preventing me somehow can anyone help me to sort this out

Hi Luke and welcome. You are most likely right that your card is the cause of this. Typically, when you add a card to a PC that has integrated graphics, the integrated graphics is disabled. This is because integrated graphics uses a large chunk of system RAM and it is assumed users want that freed up when they add a card, since the card comes populated with its own RAM. Most motherboards will allow you to re-enable the on-board (integrated) and run with both the on-board and the card in a dual monitor setup. But this has its drawbacks. First, once again, a large chunk of your system RAM will be snagged again which may affect, in a bad way, your computer's over all performance. Also, the integrated graphics may assume the role as the primary monitor which may, or may not be what you want.

My advice would be to use one of the ports on the card to feed your TV.