USB and drive letters

I have been searching but have not found an answer so in the hopes of someone
being able to help me, here is my question.

How can I get Windows to stop changing drive letters everytime a usb storage
device is connected? I mean, it takes letters that are already assigned and
uses them. I can be on a network with several network shares mounted and once
I plug the USB drive, one of the existing drive letters is used for the new
drive, this causes problems such as with applications that access resources
in the replaced drive.

Any ideas?

Thanks in advance.