I'm using a Radeon HD 3450 on Windows 7 with Catalyst 10.7
My monitor is connected through the VGA port, and it works fine.
I tried to connect my HDTV (LG 50PK350) as a second monitor through the HDMI port (on TV & HD3450). The TV (as 2nd monitor) is not detected and there is no signal on my TV.
The connection appears fine, as when I click 'Detect Displays' in CCC, the pc monitor screen flickers and tries to connect but eventually fails. (same using Windows 7 Display properties!).
I am using a brand new HDMI 1.4 cable.