First we need to download win32disk.
Insert the SD card you wish to use to backup your SD card. I would recommend double checking that you got the correct drive or data loss will occur. Extract the contents of the .ZIP you downloaded from the link above and run Win32DiskImager.exe.you will get a box like this
Using the Folder Icon on that screen, locate a place where you want to SAVE the image. You will need to know where this location and you will want to use a name that describes what the image is so that at a later date, you can possible restore it or use it to make additional copies of the image to memory cards.
This will now show the win32diskimager box look like:
Click on the read button to start the backup process.
when its at 100 percent it should say successful.