How to use the HDMI with the radeon hd 7770?

I have a dell XPS8500 with the radeon hd 7770 (win7 and Catalyst control center) but only recently decided to use the HDMI slot instead of the DMI/VGA to see if there was any difference (connected to the HDMI of my lcd tv) when i turned on the pc the computer would not want to boot with the hdmi plugged in. i... show more I have a dell XPS8500 with the radeon hd 7770 (win7 and Catalyst control center) but only recently decided to use the HDMI slot instead of the DMI/VGA to see if there was any difference (connected to the HDMI of my lcd tv)
when i turned on the pc the computer would not want to boot with the hdmi plugged in.

i was wondering how one would get the HDMI option to work on the system and in the future possibly get the lcd tv and another monitor up at the same time (currently using the LCD TV via the other option).

cheers for any advice
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