I think that what you are describing are windows in which there are a
number of small glass panes called lights. Each light is individually made
and placed in the window frame, several glazier points hold the light in
place, the light is then sealed in place with window putty. After the whole
window is repaired you'll need to paint it.
Your local library will have home repair books with detailed instructions
on how to do this. You'll need to find a source for the small panes of argon
glass. A putty knife, glazier points, and window putty will be available at
any hardware store. Last time I glazed a window I used a silicon caulk made
for windows. It was very easy to use.
Removing the old lights is usually not hard. Use the putty knife to break
out the old putty, pry out the glazier points with a screwdriver or use
needle nose pliers, and the pane should come free.