LittleLew

I have been using a Nikon D70 for about 8 months and connecting to my PC through a USB connector. Recently I installed an x-Drive Pro portable hard drive through this same USB port. (This is a PHD for graphic images). Now the USB port will no see the Nikon when it is connected altho it still works with the PHD. Is this the situation where I must 'dismount' the PHD. How does one do that in XP. No documentation on that in MS help. Thanks in advance for any advice.