I am attempting to reinstall my Canon LiDe30 Scanner on Windows XP Pro. The software packages do not recognize USB port. The scanner passes the diagnostic, Plug and Play finds the scanner, but when I attempt to select a source ( the scanner) it reports: "unable to select TWAIN source" I have removed the Canon software, I have uninstalled the USB ports, I have switched USB ports, I have downloaded the latest drivers and the latest USB patch from Microsoft. I have followed the manufactuers proceadure for reinstallation. It appears the the TWAIN files may not be recognized, where should they be and are there any other files that are required?