Question : Problem: LCD Monitor Flickers and Crashes in 3D Games

I've just replaced my old 21" Viewsonic CRT for a brand new 19" Viewsonic VE910 LCD Display today and all seems well untill i tried playing ANY 3D game! (which worked fine on my old CRT yesterday!)
The screen begins to show faint green boxes, they then begin to become stronger, and then the speakers begin to screech then the computer completly hangs!

Help me please!!

I'm running...

Computer      
Operating System      Microsoft Windows XP Professional
OS Service Pack      Service Pack 2
Internet Explorer      6.0.2900.2180
      
Motherboard      ASUS A8N SLI
CPU Type                      AMD 64, 3200 Venice MHz (10 x 200)
Motherboard Name      ASUS A8N SLI
Motherboard Chipset      ASUS A8N SLI
System Memory      1024 MB
BIOS Type      Award (04/15/05)
Communication Port      Communications Port (COM1)
Communication Port      ECP Printer Port (LPT1)
      
Display      
Video Adapter      Gainward Golden Sample 1.6ns GeForce 6600 GT  (128 MB)
Monitor                      ViewSonic VE910/VE910b [NoDB]  (PPY052620693)
      
Multimedia      
Audio Adapter      Creative Audigy Player Sound Card
Audio Adapter      Realtek AC'97 Audio [NoDB]
      
Storage      
Floppy Drive      Floppy disk drive
Disk Drive                      Maxtor 6L200P0
Optical Drive      AXV CD/DVD-ROM SCSI CdRom Device  (Virtual DVD-ROM)
Optical Drive      Generic DVD-ROM SCSI CdRom Device
Optical Drive      LITE-ON DVD SOHD-16P9S
Optical Drive      PHILIPS PBDV1640P
      
Partitions      
C: (NTFS)      29996 MB (3316 MB free)
D: (NTFS)      101065 MB (3012 MB free)
E: (NTFS)      63412 MB (45193 MB free)
      
Input      
Keyboard      Standard 101/102-Key or Microsoft Natural PS/2 Keyboard
Mouse      HID-compliant mouse
      
Network      
Network Adapter      ADMtek AN983 10/100 PCI Adapter  (192.168.1.100)
Network Adapter      NVIDIA nForce Networking Controller - Packet Scheduler Miniport
      
Peripherals      
USB Device      USB Human Interface Device
      
Sensor Properties      
Sensor Type      ITE IT8712F
Sensor Access      ISA 290h
      
Temperatures      
Motherboard      35 °C  (95 °F)
CPU      25 °C  (77 °F)
Aux      33 °C  (91 °F)
      
Cooling Fans      
CPU      2766 RPM
      
Voltage Values      
CPU Core      1.38 V
+3.3 V      3.33 V
+5 V      5.00 V
+12 V      11.97 V
+5 V Standby      4.95 V
VBAT Battery      3.02 V

Answer : Problem: LCD Monitor Flickers and Crashes in 3D Games

GPU overheating seems very likely here => 79C is HOT;  I'd hate to think what it's getting up to when you're doing intense gameplay.  The CPU temp is very good.  Try Callandor's suggestion r.e. a fan => if that works you know what the problem is;  then you either need to add a better heatsink to your graphics card; or get a new card.