Driver installation problem with Windows Vista 32bit laptop

I installed vista software (MP Drivers (1.10) and MP Navigator (3.02) )following the instructions on canon website.
When driver installation procedure is about to be completed and I get the message to connect printer with my computer, I do connect it via USB and select 'OK', then the installation ends. When restarting the computer, I get the message of unknown device connected to USB drive.When I try to open MP Navigator software, I get Error message that "Scanner driver software that supports this software is not installed. Install it and try again".
I tried to use the printer with another (vista 64) pc. At first I got the same error. After a a few trials (re-opening pc, re-opening printer) vista (i think) installed another driver automatically and it worked.
Thank you for your help
Georgia