Secondary DVI port not working.

I have an HD Radeon 6790 with 2 DVI Port and 1 HDMI port, not sure on the last. Anyway I got a 1920 x 1080 LCD Philips monitor as primary, I got a bigger LCD TV Monitor (Not sure on resolution/inch) I tried to connect it to my secondary DVI port but its not detecting.

Both on my DVI port I use a VGA adapter, so both of the monitor is using VGA connection. The first port works and detects my smaller monitor, but the second port doesn't. My bigger monitor doesn't get detected on any of the DVI ports, not sure of the problem.

Map:

VIDEO CARD - 1st DVI port => VGA Adapter => Primary monitor (1920x1080)
VIDEO CARD - 2nd DVI port => VGA Adapter => Secondary LCD TV Monitor (Not Detected*)

I have been trying to find out the issues since the past 4 hours, been searching for answers how to solve this issue but I just had no luck.

Problems:
- Secondary DVI Port doesn't work
- LG LCD TV cannot be detected on any DVI port

Normally, only one of the DVI Ports will pass through the analog VGA signal.
you will need to have one of the monitors hooked up with either an HDMI cable or a DVI cable.
Also note that one of the DVI ports is also shared with the HDMI port, hopefully it's not the one with the analog VGA output.

Give us the model of the LCD TV you are using.

I think you might be right on that, when I was searching online on how to solve this I came across a thread which was talking about not being able to use both ports at the same time so I have to buy an HDMI cable. Oh well I guess I'll try that.