how can I install cannon N670U scanner in windows 7

The newest drivers Canon has are for Vista:

http://www.usa.canon.com/cusa/support/consumer/scanners/canoscan_series/canoscan_n670u#DriversAndSoftware

You can try installing the Vista drivers in compatibility mode - it may or may not work.

Troubleshoot Compatibility 

This can help with some (but not all) programs/drivers:

1. Uninstall the program if it's already installed. Then when you install/reinstall it instead of double clicking on the install file right click it and select "Troubleshoot Compatibility"
2. Then click "Try Recommended Settings" and in the next window click "Start the Program" to install it.
3. After it installs see if it works correctly. Please note - some programs may not be able to run in Windows 7.

More details about how to make older programs run in this version of Windows:

http://windows.microsoft.com/en-us/windows7/Make-older-programs-run-in-this-version-of-Windows

How to Install A Scanner:

http://windows.microsoft.com/en-US/windows7/Install-a-scanner

Working with the Scanner and Camera Installation wizard:

http://windows.microsoft.com/en-US/windows7/Working-with-the-Scanner-and-Camera-Installation-wizard

Info for switching from Windows 7 To XP

Are you sure you want to remove Windows 7? Compare Windows 7 vs. XP vs. Vista:

http://windows.microsoft.com/en-US/windows7/products/compare?T1=tab20

If it's a new computer it might not have drivers for the older Windows system, meaning it will not work correctly.  First you would need to check with the computer manufacturer if they have XPdrivers for your computer.

Then you would need to use an available XP license you have, or buy a new one and install it on your computer. Insert the install disk into the computer, reboot, and start the install. During the install process you can format the Windows 7 partition then continue installing Windows. You'll have to backup your files and reinstall all your programs.

You can not use a Windows 7 key to activate XP.

In case you ever want to reinstall Windows 7, make sure you have a way to reinstall. If you don't have install disks, you can make a system image:

http://www.howtogeek.com/howto/4241/how-to-create-a-system-image-in-windows-7/

Installing XP:

http://support.microsoft.com/kb/978307

You can also dual boot both Windows 7 and XP.

Dual boot Windows 7 and XP with Windows 7 installed first (method #2):

http://www.sevenforums.com/tutorials/8057-dual-boot-installation-windows-7-xp.html

Have Questions About Installing Windows 7?

FAQ - Common Windows 7 Installation Questions & Answers

There is no Windows 7 native drivers, but you could try the following Windows Vista driver:

http://software.canon-europe.com/software/0027440\_0000475.asp?model=

You can then try installing it in compatibility mode:

You can find more information about compatibility modes in the articles below:

http://windows.microsoft.com/en-US/windows7/What-is-program-compatibility

http://windows.microsoft.com/en-us/windows7/Make-older-programs-run-in-this-version-of-Windows

http://windows.microsoft.com/en-US/windows7/Program-Compatibility-Assistant-frequently-asked-question