Blas :
https://www.usa.canon.com/internet/portal/us/home/support/details/scanners/support-scanners-canoscan-series/canoscan-4200f?tab=drivers_downloads
I have gone to Canon website, found their driver for Canon 4200F scanner for Windows 7: 4200fvst648620a_64en.exe.
However, installing this driver alone is not sufficient! I also need to download and install the CanoScan Toolbox v4.6 which is available under the "Software" tab on the same web page.
Once I have installed both the driver and the toolbox, the scanner works.