I have an HP Scanjet 2100C which I hadn't used for years, but used to work perfectly. I powered it up, couldn't find a driver for it so I installed a demo program called VueScan. The scanner worked, and I uploaded photos on my drive etc... Now some 10 days later it gives me the message "USB device malfunctioning" and doesn't respond at all. Has the scanner gone kaput? Or is it because I'm running off a demo program (which still works by the way)?