I have formatted and re-installed windows. I only have one hard disk drive connected, and have now tried 2 IDE cables.
I have my Leadtek 7800GT connected to one slot of the PCI-Express slots
I have disconnected my other drives, including DVD and Floppy drive
I have loaded the chipset drivers from the Asus CD-Rom, and the drivers for the 7800GT graphics card, and the Viewsonic VX922 monitor.
From the time I switch the computer on, the time schedule appears like this (in minutes and seconds) :
00:34 Windows XP logo appears
01:09 logo disappears, screen goes black
01:48 mouse cursor appears - screen is still black
02:10 "Windows is starting up..." appears, screen is now light blue
02:39 "Welcome" appears, screen is still light blue
03:54 desktop appears, although windows is still loading
05:58 Windows explorer finally opens, after trying to open it at 03:54
06:30 First system tray icon appears
07:22 "Your computer might be at risk..." message appears from the windows security alerts in system tray
After this, the mouse responds to clicks, but everything takes many times longer than normal. Looking at task manager, CPU usage is 100% and remains at 100%. All CPU resources being used by TaskMgr. Memory usage is negligible.
Running DXDiag, it recognises the processor correctly (AMD Athlon 64 3500) and the memory (2048MB). Pagefile 115MB used, 3825MB available.
DX version is 9.0c - I'm running Windows XP SP2
It recognises the graphics card, Winfast PX7800GT, Leadtech GeForce 7800GT 256MB memory, 1280x1024 16bit 60hz
It recognises the monitor as well.
It runs and passes the DXDiag graphics tests, but extremely slowly and jerkily - it really seems to be pushing the CPU to the limit.
It takes 20 seconds to shut down the PC.
I've downloaded the latest BIOS from the Asus website, and will try flashing the motherboard, but apart from that, I'm not sure whether to try to buy a new motherboard to test it, or a new CPU. I've only seen AMD Sempron's here, and I don't think they're socket 939.