Canon printer/scanner help!

Hi, i just bought a Canon mx 850 and i am having problems with the scanner. i can get everything else to work(printer, fax, copy) but i can not scan to the computer. this is the message i get every time. I have re-installed everything, i have changed usb ports still cant get it to work any help would be great thank you daniel.

Did you check you USB Controller?
Under Windows Hardware Device Manager, does it have a yellow exclamation mark.