I am very cheap by nature,
so when i decided to start working on the house, i had decided to make it as inexpensive as possible, Free is even better.
well, we have this house that was built in 1957 and the heater was bad, the grade was bad, the doors, windows and the lack of insulation in the ceiling made it vary cold in the winter and vary hot in the summer, I had decided that i need to fix the problems, and one of those projects involved replacing the windows. Well there seems to be a lot of people here where i live that like to tear down old homes and build McMansions worth millions of dollars, in the process the previous house gets mowed down, you can contact the owners and they will let you take whatever you want, (the more stuff going the land fill is equal to more money that needs to be spent.) regardless, it means that you can get stuff for free.
this instance i knew the owner and he had just replaced the windows 2 years ago, and said i could have the windows. So i went over with a screwdriver and a crowbar and proceeded to remove all of the windows. next thing i knew, i had eight relatively new windows.
and here is how i installed them in my house, maybe this will help out some one.

here is one of the windows i replaced, i did the same process for all of the windows

Step 1: Removing the Windows

this is easy, place the window in the middle of the track, grab the top and bottom of the window, push it back into its track and at the same time pull it out from the front.

Step 2: Pull Out the Tracks

use a power screw driver, goes faster

Step 3: Pull Out the Otherside

Step 4: Clean Up the Tracks

now you have hole that needs a new window.
i used a paint brush to clean up the dirt left behind

Step 5: Frame the Window in to Fit Your New Window

i used one side of the track for a template on the 2x4

i had to shim out the 2x4 1/2 inch on one side and 1/4 inch on the other side.

(i built this table and posted instructions in one of my last instructables.)
It has turned out to be a very robust table, i use it for everything. and it can support well over a 1000 lbs.
table