If they are the sprial balances listed by NEEDWINDOWS then all you need to do is measure their lenght. The distance form the red or similar color plastic at the bottom to the top of the metal. Each sash has a left and a right - both the top and bottom sashes have two each. You need two tools to remove and install new balances. You need a phillips head screw driver (a screw gun is easiest) and a balance adjusting tool. The balance adjusting tool can be purchased from the balance supplier. They are usually not available in your local hardware or big box stores. After you recieve your new balances and are ready to replace the defective ones you'll have to first tilt in the bottom sash and then tilt the top sash right on top of it. Now all four balances should be exposed. Sometimes the balances are covered with a piece of vinyl trim, just take those off. The top of the balance is screwed to the vinyl. Look at the bottom of the balances and see how they are attached to the vinyl window shoes in the tracks. Practice using the balance tool by attaching it to the bottom two pins at the direct bottom of the balance. Hook the claws over these two pins, gently pull the balance out of the shoe with the tool attached and turn counter clockwise. Hold the tool tightly in your hands. if you feel tension on the tool then the balance is probably OK or may just need a turn or two to tighten itself up. Hook the balance back into the shoe. Check another one. If you feel no tension on the tool when you hook the pins and pull down a little then the balance either can be defective or just has to be re-wound. Sometimes it take 5 - 7 clockwise turns to start the balance to start tightening and pulling up. Don't over tighten it. Then it is time to re hook the balance into the shoe in the side track of the window. If you try to tighten the balance and you hear a clackety-clack, then the balance is broken. Replace it by unscrewing the screw at the top and installing the new one the same way. Remember to study how the balances are attached to the shoes before removing them so you know how to put them back. Since you said you are handy, with a little patience and some practice, you could repair them yourself. If it seems to be too difficult for you, contact your local replacement window dealer for help. Although he'll probably try to sell you all new windows, tell him you just want the ones you have repaired. Good Luck All The Best, The Porch Guy

Can you take a picture of the balance assembly? If the window is relatively new (under 10 years) it might be something that is covered under warranty.

Hi Texas_Al, It sounds like the bottom pane may not have been seated into the carriage in each channel? When we pop the bottom pane out for cleaning, there are four points of contacts; one at each corner. The top two is released by flipping a sliding switch by the latch. This retracts the inserts from the channels and lets us tilt the top of the window out of the opening and into the house. Then we lower the window until it is horizontal and the bottom two contact becomes visible in the channel, one on each side. The two contacts or inserts in the bottom corners of the window pane are actually sitting in carriages; one on each side in the lower channel. We have to lift one side of the window off the carriage in that corner so it clears the opening on that side, then we lift the other side to clear before taking it out. To return the window pane, the key is in the carriage in the channel on each side. The carriage is just a little gizmo with a thick string attached. The bottom inserts of the window must rest in the carriages, one on each side for support. This means reversing how we removed the window pane earlier. These carriages supporting the bottom corner inserts support the bottom pane while the top inserts just keep the windows in the channels. It sounds like your difficulty is with the windows not properly seated in the bottom carriages? I am unsure but may be during cleaning or removal process, the carriage were accidentally retracted to the bottom of the top channels so it is no longer in position to receive the bottom inserts of the window? If you look in the channel about midway between the top and bottom panes, is there anything smallish in the channel with a slot? Something that can act as a carriage? If there is, may be a screw driver inserted into the carriage can slowly pull it down into position so you can then insert the window again? I will suggest that before working on the non-functioning window, take a look at one that works, so you can better identify the bottom carriage applicable to your model. Our windows are 5 years old so this will not work if yours have a new design. Good luck!

Usually it is best to just replace both tracks. The foam on the back side of tracks gets broke down over time and they should come loaded with a new spring. Other manufactures tracks usually work but sometimes you need to replace the cams on the window that ride in the cam shoe on the window.