In the Folder Options window slect the FileTypes tab.
Move the slider around to find the file extension of the type of file who's icon you want to change. Click on the Extension once.
In the 'Details for
You get an 'Edit File Type' window and the first button is "Change Icon..."
In the 'Change Icon' window browse for the icons you saved, they should appear in the pane below. Click one and then OK.
OK and close your way out.
From now on any file with the extension you chose will be represented by the new icon.
