Question : Problem: how to stop the external hard drive from turning on and off with the computer

i have an external hard drive Lacie Big disk attached via usb connected to my pc running vista ultimate.  when i turn on the computer, the external hard drive turns on as well.  is there a way keep it from turning on and off automatically with the computer without "pulling out the power cord"?  i

Ideally,  would like to be able to manually turn the external drive off and on by pressing the power button on the front of the drive.  Or, i would like to be able to manually turn the drive off and on via the desktop with a simple command.

Answer : Problem: how to stop the external hard drive from turning on and off with the computer

The only solution with USB is to buy an enclosure with a ON/OFF switch, like the Vantec NexStar NST-350U2. This is one I'm using, but there are many others.
You can install the hard drive you presently in such an enclosure.