What OS are you using?
I'm not familiar with Vista, but if it's XP you have to make sure it's Enabled.
Go into the Control Panel and double click System.
On the Hardware tab push the Device manager button.
Open the Disk Drives list and double click the drive in question.
At the bottom of the window there's a drop down for Enable or Disable.
Choose Enable.
Also, while you're there, go to the Policies tab and make sure the "Enable write caching on the disk" box is checked.
That should get you going.

Ken

__________________
(\__/)
(='.'=)
(")_(")