When I first got my kit and put it together, I was getting a CPU speed of around 1.166MHz - no wonder it was running at 35°C - lol. I changed the BIOS settings: CPU Ext. Freq set to 200MHz (up from 100MHz) and CPU multiplier set to 10.5 (down from 11.5) giving a CPU speed of 2.1GHz. However, this was after I took the Radeon out. Would the Radeon have been upset by that low CPU freq. setting? The documentation suggests that the Radeon is very much downward compatible...
Voltages. I attach a snapshot of the Asus utility voltage monitor. The 5V supply is not quite making 5V, and is not quite as stable as the others. Might this be a problem?

Finally, is there a second best video card that can be recommended? If these matters are not going to help, I'm going to be stuck with a card I can't use. You can bet that if I ask for another Radeon 9800 from the same supplier, I'm going to get the same card back... The only other thing I could do is get a refund, and then go and buy another Radeon 9800 from somewhere else, and exchange it if it doesn't work.
Replicant - thanks for your offer, but I don't want to alter the card in any way else they'd never take it back if that fix did not work.