Have you had your printer for awhile and recently upgraded your operating system to Windows 7? If so, you need to download a new printer driver (and software) from the Canon website for Win7.
I recommend that you uninstall your printer and software before re-installing the software from the following link at Canon support:Canon
Choose your operating system (Windows 7 or Windows 7 x64) from the drop-down box.
Download the driver file and any additional software as needed.
Run the driver installation routine and follow the prompts to re-install your Canon MP730 on your computer.
Run the install routine on any additional software.
I hope this helps!