I have a P5B-e and saw some others had issues with the eSata being seen by windows and so I signed-up to let you guys know to just go to asus downloads here: http://support.asus.com/default.aspx?SLanguage=en-us
select your socket and board, etc. then select LATEST
for drivers download. d/l the JMicron JMB363 RAID Driver V18.104.22.168 WHQL for Windows 2000/XP & 64bit XP & 32/64bit Vista.
eventhough it says RAID only, it DOES have the driver for SCSI/hot-swap devices, too! just run it within Vista or XP and select the appropriate tick-box and restart and BOOM!