3 years ago I had new windows put in the house. All except for three in the bedroom and one in the laundry room. I had already bought a window for the laundry room, and they wanted $600 extra for the three 2' x 2' windows on the east side of the bedroom. So, I decided to do it myself. Up until yesterday when I started the project, they were old 1940's single pane windows that I had covered with a couple levels of plexiglass to help insulate them. Which meant that although they kept the heat in pretty well, they not only didn't allow me to open my windows in the summer, but they looked like hell too. I bought three 2' x 2' double paned vinyl windows sometime this winter, and just had to wait for school to get out so I could install them.
The first one went quite well. The hardest part was getting the old window out, since I had sealed the plexiglass with silicone caulking it wasn't too eager to come out. I ended up breaking the glass and demolishing the window frame. I don't care about the frame, I'd be tossing it whether it was intact or not, but the glass is certainly a pain to clean up. But that's ok, it went in really easy, and looks pretty good for an amateur, if I do say so myself.