Why would you want it disabled ? Surely thats the point of an ACCELERATED graphics port ? Why not just have it enabled and do away with the option in the bios, thereby saving space on the chip or whatever ?
Fast writes are part of the AGP protocol and are meant to speed up the transfer of information between the video card and system memory.It was meant to increase performance during game play (for example), however not all computers could handle the high data rate and there were frequent computer crashes as a result.Even if it worked without problem there was usually little or no gain in performance.For that reason it was almost always either disabled by the video drivers or in the BIOS in the name of computer stability.MAny graphics cards did not support fast writes at all.
The situation with high definition video might be different as the amount of information needing to be shifted about is huge.Not only that but they may well be optimised for fast wtites so work better with it enabled.Looking at the recommended spec pc required then you are looking at near state of the art to get the best out of HD DVD so there should be no problem running fast writes on such a machine.Furthermore I think that all modern graphics cards/drivers and chipsets will support fast writes.
With your pc you will have to go into the BIOS as instructed above by Yoda Knight and find the graphics/agp settings.Make sure that fast writes are enabled then reboot into Windows.Then you will need to check that fast writes are enabled in your video driver controls(rt click on the desktop,then click on settings......advanced and select the tab for your graphics card).When you have them enabled run the test again......if it runs ok then just leave them enabled and use your pc as normal......and enjoy your HD DVD's.
Please bear in mind that fast writes are not the same as the agp acceleration in general,they are a seperate set of instructions to improve the performance of agp graphics.So please don't disable your agp acceleration whilst you are in the BIOS or you will find yourself struggling to watch any video not just HD ones,lol.