This is not directly relevant to your situation since you're running Windows, but I thought I'd answer anyway in case a Linux user comes across this question.

On Linux you can use the Net::DBus module to to subscribe to notifications from HAL (the Hardware Abstraction Layer). The Net::DBus::GLib module allows easy integration with a Gtk app without needing to use threads. An example of an app that does this is my usb-key-copy-con a Perl GUI tool for automated copying of USB storage devices.