Possible Duplicate:
3 Monitors on Sapphire Radeon HD 6870
I have an Asus Radeon 6870 with four places to connect a monitor.
I am using three 1920x1080 monitors, connected to the following ports:
Card Monitor DVI --------------------> DVI HDMI --------------------> HDMI Mini DP ----> Convertor ----> DVI
This is the convertor I use: Mini DisplayPort to DVI converter
My card detects all three monitors, but when I go to extend the desktop onto the third monitor, this error comes up and I cannot get all three to work at the same time.
"To extend the desktop, a desktop or display must be disabled." with "Continue" and "Cancel" as options.
I tried the left DVI, the HDMI and I have tried both Mini DPs with the adapter.
I have looked at the other thread on this site in order to solve this problem, still no working solution.