I just got a new computer yesterday and I also have been having this problem - the friendly and enemy icons flicker between red/green and gray/white. . .
its odd because this computer is better - stronger in everyday to my previous laptop. . .
while i agree that dell is not the way to go for desktops, my computer is a research gift from the Japanese government, and they do not accept 'home built' computers.
Current computer:
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System Information
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Time of this report: 1/25/2013, 00:46:26
     
   Operating System: Windows 7 Professional 64-bit (6.1, Build 7601) Service Pack 1 (7601.win7sp1_gdr.120830-0333)
           Language: Japanese (Regional Setting: Japanese)
System Manufacturer: Dell Inc.         
       System Model: Inspiron 7720
               BIOS: Default System BIOS
          Processor: Intel(R) Core(TM) i7-3630QM CPU @ 2.40GHz (8 CPUs), ~2.4GHz
             Memory: 8192MB RAM
Available OS Memory: 8048MB RAM
          Page File: 3491MB used, 12604MB available
        Windows Dir: C:\Windows
    DirectX Version: DirectX 11
DX Setup Parameters: Not found
   User DPI Setting: 96 DPI (100 percent)
 System DPI Setting: 120 DPI (125 percent)
    DWM DPI Scaling: Disabled
     DxDiag Version: 6.01.7601.17514 32bit Unicode
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Display Devices
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          Card name: Intel(R) HD Graphics 4000
       Manufacturer: Intel Corporation
          Chip type: Intel(R) HD Graphics Family
           DAC type: Internal
         Device Key: Enum\PCI\VEN_8086&DEV_0166&SUBSYS_05781028&REV_09
     Display Memory: 1696 MB
   Dedicated Memory: 64 MB
      Shared Memory: 1632 MB
       Current Mode: 1920 x 1080 (32 bit) (60Hz)
       Monitor Name: 汎用 PnP モニター
      Monitor Model: unknown
         Monitor Id: CMN1720
        Native Mode: 1920 x 1080(p) (60.002Hz)
        
            
my previous computer ran with a 512 graphics card and a weaker chip. . this one can switch between its Intel HD Graphics 4000 GPU and Nvidia GeForce GT 650M GPU with 2GB of VRAM. . .not ideal, but sadly I have to play out of laptops till I settle.