Though not completely identically, I have reported similar behavior.
The system here is and Intel based mainboard/CPU and W XP Home with RAID1.
My problem is that on cold boot the first drive fails to be recognized every now and then (3 week interval) but still starts Windows XP.
Thereupon it starts showing the "disks" and shows a failure of disk 2.
I disabled the drive cacheing functions to see if that would solve the issue, but no result.
The system log however only reports iastor0 (first drive) timing out (error IDs 9 and 7024).
Yet the second drive is set to "failure".
Testing th drives with the manufacturer's diagnostic tools never have shown a failure on either drive.
I therefore presume it's either the driver or the management software that's causing these situations over and over.
Did you check the system (evetually the application) logs?
In the logs I also found repeated errors of the Windows Search function, so that could also be part of the problem.
After "killing" the management software I have not yet seen a return of this error nor that of Search (each day sometimes all over the 3 weeks period!).
But... recall the three weeks of proper functioning! So the issue perhaps is yet not resolved.
Hopefully you'll find something here or through my error description.
My other thread has probably been a waste of time as nobody seems to care to reply.