I have a Maxtor 500 gb external HDD, but every time i plug in the usb cable the internet cuts out, which is connected via a belkin wireless adapter, i emailed belkin and they said it wasn't the adapter it was something to do with the usb, i have had this problem for a long time and spent many an hour searching for a solution, just to add this hasn't always been a problem when i first got the drive it worked fine along side the internet adapter
The Hard drive is sharing a port/channel with the Belkin device. Guess who has the priority? The Hard drive.
The hard drive is going to nearly capture the port and will be streaming far more data than the Belkin.
They are both serial devices. Get them on their own ports and your problem will go away.