After 14 years nearly every window has at least one foggy pane. I can replace the panes, but will the problem reoccur as quickly? What happened?
There really isn't a repair, other than replacement. If you have the manufacturer's name and contact information, you may be able to contact them to have the individual panes replaced. If not, you are probably looking at replacing the windows again or living with the fog.
You may be able to get a whole new sash rather than just have the glass replaced, probably be cheaper and for sure a lot easier.