i have an iomega 120gb external desktop drive. it connects via usb 2.0 and has been working perfectly for 8 months. however when i plug it in now, my computer takes ages to pick it up, and furthermore, the drive switches itself on and off constantly every minute or so. when the drive is not connected to my computer it not longer switches off by itself. when i connected it to another computer, that computer froze until i disconnected it. what's wrong???