You might want to also consider the use of Windows XP Mode and Windows Virtual PC, Windows XP Mode works in two ways – both as a virtual operating system and as a way to open programs within Windows 7. In some cases, you can install hardware devices and use the drivers designed for Windows XP within Windows 7 via Windows XP Mode and Windows Virtual PC. This will not work in every scenario with hardware compatibility concerns however it will work in some.
The Windows XP driver for the Canon LBP 800 Laser Printer is available from Canon here.
Another option would be to try to install the printer driver within compatibility mode.
For your convenience I have included the instructions for Compatibility Hardware Device Drivers by Microsoft MVP, Ronnie Vernon, from the TechNet forums:
COMPATIBILITY HARDWARE DEVICE DRIVERS:
1. Place the driver installation file on the Desktop.
2. Right Click the driver installation file and select Properties/Compatibility Tab. Select the appropriate options in from the list. In your case, you would select Windows Vista.
3. Click Apply/OK.
4. Right Click the file and select the Run As Administrator option to install.