Windows 7 will not install drivers for canon 8400 scanner

Did you Install the software before hooking up and powering on the scanner as instructed in their quick user's guide ? It is definitely compatible with Win7 64bit, so that may be the problem.
http://safemanuals.com/annexe_CANOSCAN%20208400F%2020QU...

Yes, I tried to install the drivers before hooking up the scanner.

As I said originally, I can't get the drivers to complete their install so I never get to the stage of hooking up the hardware.

What could be preventing the successful install of the drivers ?

Anything reported in event viewer ?
If no errors there, and no on screen errors while installing drivers,
hook up the hardware, see what happens.

I'm not sure what I'm looking for in Event Viewer, but having taken a good look at the entries there is nothing that looks related to the problem I'm having. Can you help by telling which of the categories I should be looking at and what I should be looking for ?

Another point, I have the original scanner install CD (but for an XP) and I tried to install the drivers from that (with the intention of updating them after the install). Again, it appeared to go through the install process but didn't complete with a success (or failure) message. When I checked, no drivers had been installed.

I tried hooking up the scanner but it said that there were no drivers present and no drivers could be found to install.

I'm baffled with this problem. Never had any difficulty with installs before and laptop work perfectly other than this problem.

Thanks for your interest so far, any more ideas?

Any error (if any) would probably have been in the System or Application TAB, and would be indicated with a RED X. The others (I) are just informational messages. Looking there, was just a thought.

The only other thing that comes to mind is that to RUN group policy edit
(gpedit.msc) from command prompt. I know there is a setting in Account Policies > Local Policies > User rights for device drivers assigned to administrators. Might click on all items under Policies and look in right hand pane to see if anything doesn't look right with respect to who can do what.

Nope, no RED X or the like.

I've already tried gpedit.msc from the Run box and it gives - No items match your search.

From Command Prompt the response is - "gpedit.msc is not recognized as an internal or external command,operable program or batch file."

23.00 now here in the UK, off to bed now, will 'speak further in the morning.

gpedit.msc is Not available in Home Premium or Starter for Win7, I saw in another Post I guess there are ways to add it, though I have never used any of these links/products.
http://add.fanhow.com/add-gpedit.msc-win7-

If you were able to install drivers on this system before, and now you cannot, then you may have to windows restore to date when you could, or repair-install the OS from Windows CD.

If you can install other device drivers, then I think you have to assume there is something with the download for this particular device that is causing you grief.

I've now managed to get the scanner drivers installed.

I tried many times and in many ways to install the drivers by downloading them and installing. Each time the install started but never finished so the drivers weren't installed. I tried in Safe Modem with Firewall off etc - all installs failed.

Then a brainwave ! I made sure the drivers were downloaded and in a folder in 'Downloads' on my laptop. I switched off the laptop, connected the scanner and switched on. After starting up it detected the new hardware and automatically started searching my disk for suitable drivers. It found my folder containing the downloaded drivers and successfully installed the drivers.

I checked Device management and the correct drivers are showing as successfully working.

Eureka !! Job Done !!

Thanks for the time you've spent on this. Hope this solution is helpful to you.

Greeting from Bonnie Scotland !!