Trouble unmounting USB devices

[Kevin Kempter]

Hi all;

I have 2 devices that I use often.

1. a 1Gig memory stick via a usb emory stick reader
2. a 40Gig Firelight USB2 exterenal hard drive

both devices are immediately recognized and have no problems with usage. 
However much of the time I cannot unmount the device. I get a message 
that says the device is busy. I have no windows open which are "in" the 
device directory.

Any ideas?