canon printer

I run xp and I have a canon imageclass mpc190 (scanner, copier and printer).It has a usb connection. I keep having problems with it. If I want to work with the video or digital cameras the printer must be off and the printer won't work if these devices are connected. Also when I have the printer only connected the scanner plays up tells me - action can't be completed because the other program is busy. Choose "switch to" activate the busy program and correct the problem.What other busy program there isn't any. Please help

[R.I.P.]

Jane ...how many USB ports do you have on the P/C and are they all enabled ....?

let us know

dl65  

i have two usb ports in the computer one has the modem in it and the other has a four port usb hub in it. as far as i know when i go into device manager it tells me i have conexant usb network interface, generic usb hub, 2 usb root hubs and 2 rev5 or later usb universal host controller. these are all enabled.