been there , done that, i dont know about the previous replies mate...
Why should you operate on IDE66 ? , you paid for a fast board, you should get one.
This sounds the same problem i have with my ASUS A7V133, it crashed ALOT, i have done about 25 different attempts at installing and reinstalling drivers / BIOS / OS's etc.
the first thing to do is pull out every PCI card,then reinstall everything from scratch if it is not too much trouble.
The sequence you install everything is VERY important.
Here is what i do (courtesy of another TOMS' poster)
First ,plug your HDD into the IDE66 plug,
set bios to boot from the CDROM first.
Bootup with windows CD.
create new partitions (to wipe the drive),
make the new partition for the OS smaller than 8 gig.
install OS
install modem
go to microsoft updates site, download and install 128 bit encryption pack.
do every download until there are no more updates.
Install the 4 in 1 drivers, noting that there are now new
drivers on the ASUS website
(http://www.via.com.tw/drivers/index_new2.htm)
When you install the 4 in 1 drivers , carefully follow the installation guide ,as the RAID driver has precise instructions or it will not install.
You can then change the HDD over to run off the ATA100 plug.
install all other PCI devices one at a time, and reboot after each one.
After doing all this, my system is better, but not perfect.
I still get problems with my printer hanging, and small crashes , where win2K asks me to debug the corrupted files.
I also sometimes get corrupted data when doing file transfers, even with the newest 4.31 drivers.
I think they really need to recall this board.