When you restart Windows XP, it does NOT consistently detect the IEEE 1394 hard disk.
You receive an error similar to:
<Drive_letter:>\ is not accessible. The network resource or device you are trying to access is no longer available.
Microsoft is aware of this problem, but no solution is currently (March 2003) available.
You can try the following workarounds:
1. Unplug the drive and wait 15 seconds before reconnecting it.
2. Power off the computer, wait 10 seconds before turning on power.