I downloaded Lexmark X3550 Drivers 'cjb3500-4500en' for Vista, but Vista doe not find my printer. USB ports are working fine, but when I connect Printer, nothing happens. What can I do?

I checked this printer is vista ready. I faced similar problem with webcam. Try adding hardware. Go to control pannel click on add hardware-> next and see if the printer shown. Follow the prompts and printer will be installed.(Normally the software is installed first and then prompt comes to connect the printer. When you connect the printer it will detect automatically.)