This is KD 113343 on FamilySearch:
How to install drivers for a Canon MS 300 or MS 300 II scanner
Computer Specialist Information
Start by checking the scanner in Device Manager. To get to Device Manager:
Click Start.
Right-click Computer (Win XP: My Computer).
Select Properties.
Select the Device Manager link on the left (Win XP: Select the Hardware tab, then the Device Manager button).
The Canon scanner should show up under Imaging Devices. If it is under Other Devices, the correct drivers have not been installed. If you are using the Canon MS 300, you must also check the status of your SCSI device (either an Adaptec SCSI card, or a RATOC* cable) and make sure it is recognized and installed.
User-added image
If you are using the Windows 7 ver 2.0 image (see Finding the Family History Center Desktop Image version number (53232) ), you can do the following to install the needed drivers for the Canon MS 300 or 300 II scanner:
Note: If you have a Canon MS 300, you will need to ensure that your SCSI device is installed BEFORE installing the scanner.
Open My Computer (Windows Explorer) and navigate to:
C:\DIS Drivers\Scanners\Microfilm-fiche\Canon\c300ii
(Note: The c300ii drivers will work for BOTH the Canon MS 300 and MS 300 II scanners.)
Run BOTH the Setup.exe files located in the All Drivers and TWAIN directories.
Next, go to Device Manager (see the steps above), right-click on the Canon MS 300 scanner, and choose Properties. Select the driver tab, and choose update driver. Select the option to choose your own driver, and navigate to:
C:\DIS Drivers\Scanners\Microfilm-fiche\Canon\c300ii\Win 7\32bit\INF or
C:\Support\FamilySearch\DIS Drivers\Scanners\Microfilm-fiche
Then click OK so the inf file there can be installed.
Open XnView, choose File, select TWAIN source, and then select the Canon MS 300. Click File and Acquire, and you should be able to scan.
If you run into problems or have additional questions, please contact FamilySearch at:
https://www.familysearch.org/help/contact
*The RATOC (U2SCX) SCSI to USB cable can be installed on the Windows 7 ver. 2.0 computers by doing the following:
Make sure the Canon MS 300 scanner is turned on before the computer is started up. If it was not, leave the scanner turned on, and restart the computer.
Log in as an administrator.
Click Start, then Computer.
Double-click the C: drive.
Double-click the DIS Drivers folder.
Double-click the Ratoc Cable folder.
Double-click the U2SCX_64 file to run it.
If you see a screen with odd characters, just give it a few seconds, and it should continue automatically. If it does not, and you are prompted to choose Yes or No, select No.
Follow the prompts to continue the install.
When the install is complete, next you will need to install the Canon drivers (go to step 1 under: "...do the following to install the needed drivers for the Canon MS 300 or 300 II scanner:" above.)