How can I replace an aluminum window spiral balance?
At the end of the spiral balance is a small hole... you will need a tool for this... (look on line and buy one ) it has a small hook on it... move your spiral up by hand until it stops... take  the tool insert tip into hole  and turn the spiral about 10 times... ( clockwise ) ... then using that same tool move the spiral up in to the area that will hold it...( this might not be easy ) but it will kind of be on a ledge that will hold the two small pins... the tension will hold it up... do both sides so the number of times is 10 and giving the same tension on both sides.... slowly raise the window... 
Good luck !