Hi there
just download vmare player or vbox. (both FREE).
install it and then run the "Create Virtual Machine Wizard".
This will install your XP system -- you need the XP install disk.
Once your OS is installed just start your Virtual Machine software - then you'll be presented with your standard XP logon screen. Switch to full screen and you've now got a fully working XP system.
This will run quite happily on Windows 7 Home edition.
After first boot of your VM run the "Install vmware tools" or I think in VBOX it's called "Additions". These add things like Sound
driver, optimize the mouse and graphics etc etc.
Plug your USB devices in - and install the
drivers just like as on a real machine.
There's plenty of info on the VIRTUALISATION section on the Forum.
Don't give your XP VM more than say 640 MB if you only need the scanner etc.
Cheers
jimbo