Exten 3 Monitor ไม่ได้

รูปตามนี้ครับ >>> http://www.uppic.org/share-E9B7_518363FA.html
------------------------------------SPEC---------------------------------------------------
>>>>>>>>>>>AMD Radeon HD 7900 Series
OS Name    Microsoft Windows 7 Professional
Version    6.1.7601 Service Pack 1 Build 7601
OS Manufacturer    Microsoft Corporation
System Name    USER-PC
System Manufacturer    System manufacturer
System Model    System Product Name
System Type    x64-based PC
Processor    Intel(R) Core(TM) i5-3350P CPU @ 3.10GHz, 3101 Mhz, 4 Core(s), 4 Logical Processor(s)
BIOS Version/Date    American Megatrends Inc. 0301, 8/5/2555
Installed Physical Memory (RAM)    4.00 GB
Total Physical Memory    3.95 GB
Available Physical Memory    2.11 GB
Total Virtual Memory    7.91 GB
Available Virtual Memory    5.24 GB
Page File Space    3.95 GB

-----Port ที่ต่อ----------
DVI Port
HDMI port
Display Port

ขอขอบพระคุณมา ณ โอกาสนี้ครับ