I was able to get this scanner going by following Route 44's advice; I found the disk and reinstalled and it worked.
Of course, now I've bought a new computer running on Windows 7 and must try and figure out why the driver I have repeatedly tried to download doesn't seem to be working...must find some time to resolve this latest issue. Sigh...
Canon is showing drivers for Windows 7 even for the older model 8400F, (which I own). That being said, I haven't actually tried them yet.
FWIW, I just couldn't find the driver that I'd downloaded from Canon USA website (all that appeared in my software file was "read this"). So for grins I uninstalled everything that I'd downloaded and inserted my old disk (based on XP, I thought). Installed Toolbox and all accessories...voila! Works just fine. I assumed I'd need Win7 software...you know what they say about people who assume things...makes an '***' out of 'u' and 'me'.