Power off drives on stopping in Vista & Win 7
When you safely remove the device in Windows XP it powers the device off – in the case of a flash drive its led was switched off and in the case of a portable hard drive it was spun down. But Microsoft changed this behavior in Vista and it still exists in Win 7: after you stop the device on these OSes the hard drive continue spinning and flash drive continue lighting. All modern hard drives park theirs heads automatically when you unplug them so in theory this behavior shouldn’t lead to loss data or damaged drives. But in practice the hard drive usually sound strangely when you unplug them on run and this makes a hard drive owner being a bit nervous when he hears that

USB Safely Remove can change this behavior and make the system power down USB ports. In order to enable this feature just answer "Yes, please" when USB Safely Remove suggests you to enable it.