Firstly can you check to see if your windows 7 32bit or 64bit.
Windows logo bottom left, then find computer on the list on the right. Right click it and go to properties.
It should tell you about halfway down under "System"
"System type: 32-bit Operating System"
"System type: 64-bit Operating System"
Before starting the driver installation, connect only the LAN cable first, do not connect the USB cable at this time.
This is necessary for your printer to acquire IP address automatically before you start the driver installation and enable driver installer function.
Driver and application software files have been compressed.
The following instructions show you how to download the compressed files and decompress them.
1. Connect the printer to your network using LAN cable. (If applicable)
2. To download files, click [I Agree-Begin Download] icon, select [Save], and specify the directory where you want to save the file. Click [Save] to start the file download.
3. Downloaded files are saved in the specified folder in a self-extracting format (.exe format).
4. Double-click the files to decompress them. A new folder will be created in the same folder. The new folder will have the same name as the compressed file.
5. Double-click the decompressed Setup.exe file to start installation.
6. After the drivers have been installed, connected the USB cable to the printer. (if necessary)
I would suggest removing all traces of the printer first if you have a printer added which doesnt work delete it from devices and printers prior.
Link to the drivers for your printer, make the choice of default or x64 based on your results for operating system.
Canon U.S.A. : Consumer & Home Office : Color imageCLASS MF8050Cn