Flickering screen with hdmi and not vga

hello,

I have a 40in samsung lcd model # LN40C530 and ATI hd 5670 running on win7 ultimate with 2 gig ram and athlon II X2 250 3ghz processor.

I'm trying to run both vga and hdmi at the same time so i could just hit the source button on my tv and switch back and forth. When running just vga by itself (hdmi not physically connected) the screen is fine and vice versa.

When I connect both cables the pc acts like there is two monitors (like there is a ghost monitor sitting to the right of my tv). vga shows the left side where all my shortcuts are on the desktop. when i change source to hdmi it is the ghost monitor (right side). I can see the mouse and all that but the problem is when I move VLC player or any other player over to the hdmi side the video flickers on the bottom half of the screen. I've got all the latest drivers and have messed around with some settings in ccc but must admit i don't know what i'm doing. How do I fix the flicker and still have both connections? Also if I can fix the flicker, how can I eliminate the "ghost monitor."

FYI- the reason for doing both connections is when reading any kind of txt on hdmi by itself (like web pages) it is very hard on the eyes and doesn't look right. looks fine on vga. so i want to use vga when looking at websites but hdmi when watching movies. already found out that its my particualr tv thats causing that problem so not much i can do about that.

Thanks for any help.