:drool: I have a machine that is the main 100% stable, however the graphics card is causing me real reason to worry and no one to date seems to be able to point to a cause. I installed the machine from scratch with a clean formatted system disk. I installed XP Pro (S1a edition) I installed DFI drivers Upgraded to SP2 Installed Drivers from supplied ASUS CD Installed 3dMark05, Aquamark03 (+ patch), PCMark04, Sandra, Prime95 Installed Nero 6, Nortons Internet Suite (and disabled all but AV) Installed HL2, Far Cry, GP4 and Combat FS3. I ran Prime - 10 hours - no errors, Memtest 1.51 - 5 hours - no errors Ran all the benchmarks without issues and got good figures. At this point, I put the Asus CD in again to install Smartdoc - as it began autorunning setup, the PC hung and after 20 seconds rebooted. This happens every time I run (autorun or otherwise) the CD setup program, downloaded versions of Smartdoc or Asus VGAInfo. This same problem had happened with my previous EAX800XTPE which ASUS said was probably a fault with the card so I RMAd it. I have since removed all the Asus s/w - Enhanced Driver, Display drivers, uninstall util and Control Centre and successfully installed the latest Catalyst. The next problem occured when I ran HL2 for the first time and set options. Before playing for the first time, I set display options to 1600x1200 with max of all. I then selected play game. The screen resync'd and put the usual blurred background up whilst it loaded. After a few seconds an Engine Error occurred - 1. Engine Error - Failed to lock index buffer in CMesh DX8::Lockindex buffer this was followed by 2. Application Error - The instruction at "0x241f94b7" referenced memory at "0x010800cc8". The memory could not be read. Click OK to terminate program I hit ok and then rebooted the machine (I chose to !). On reboot first the memory check pre BIOS screen and then the XP Splash screen appeared with a superimposed matrix of white blocks covering the screen. Following the XP Splash, I got a blank black screen with some disk activity and then nothing. I had to power off and on. Since then, I've had no repeat of this problem. Has anyone seen something similar before. I'm desperate to get to the bottom of this and I'm praying it's Asus s/w related but the latter problem is worrying. Paul.