Unmounting a USB external drive issues

Hey there!

First off, I run Vista Home Premium. I'm having problems unmounting a USB
external hard drive - when I try to use "Safely Remove Hardware" (whether
through system tray icon or through "Computer"), the system ALWAYS tells me
it's still in use, even though I've shut down all programs using it and I'm
not writing to it at the time.

When I go to "Device Properties" -> "Policies", the drive is set on
"optimize for quick removal" option. Does that really mean (as I've read on
another site) that I can just unplug my USB cord after I'm done writing to
the drive, without attempting "Safely Remove Hardware" procedure? Is there a
certainty that it won't damage the structure of my hard drive or lose any
data on it?

If not, please advise me how best to safely unmount/eject my external hard
drive, short of having to shut the computer down. Thank you so much for your
help!