Canon mp810 won't scan

[pk5157]

My near new mp810 multi "everything" printer keeps saying it "cannot communicate with scanner, cable may be disconnected or printer may be turned off. Check status. Scanner driver will be closed."
It prints fine and even copies fine. I have swapped cables (always was a short length cable) , changed cable's USB plug in point positions. Nothing but the above message. This is on my desktop.
When I go to control panel, "scanners & cameras, it does not appear as a scanner and the Wizard won't start either. I have reinstalled the Canon software about 6 times and I have uninstalled previous Canon scanner drivers using Canon's supplied software.
The printer scans fine when I use my laptop, so it must be my desktop setup somewhere. No device driver errors or apparent problems. It's driving me crackers !!! ( Running up to date WXP Pro, P4 3.0 chip.)

[theengel]

Try looking in your device manager at the USB ports. Are they listed as USB2? It seems like sometimes there's a lot of problems getting USB2 drivers to work. I can't remember how to do it, but try reinstalling the drivers. Go to the USB ports in device manager, and say update drivers. If you don't have any USB2 drivers available in your list of available drivers, see if using the standard USB1 works..