Can't transfer music, or video to Archos

[pjc]

Hi guys, please help.
I have tried to transfer some music, and videos from my laptop to my Archos (which I have done many times before) by for some reason tonight it's not letting me.

I attach the usb lead to the laptop, and plug in to usb B on the Archos.

I then get a message on the Archos saying "USB cable attached Windows Device"
But nothing happens.

When i have transfered files before it has done so automaticaly.

Am I being thick?? lol
Please help.