I have a Hewlett-Packard ScanJet 5300, and it is a piece of junk!! It does just what yours does; even though it's plugged in and connected, whenever I go to use the software I get an error message that it "can't find my scanner", so I have to reach around and unplug/replug the cords. Then, when I do the first scan, it doesn't detect anything and I have to scan everything twice. I have uninstalled and reinstalled the scanner and software countless times over the past 2 years, downloaded updated drivers, etc., and no improvement. It's the only thing on this PC that I haven't upgraded since I got it - - probably since I don't have to use the scanner too often so I just put up with it. I also disabled the scanner buttons, since I kept hitting them accidentally and printing out totally black pieces of paper that sucked up an entire print cartridge........