Second Chance, Inc is a non-profit which takes in sashes, shutters, doors, mantels, from remodeling projects or demolitions. You get a tax credit in return. While they are located in Baltimore, you likely have something similar in SC. Here is a link that might be useful: Second Chance, Baltimore

Well, I used to be die-hard fan of Zinsser products and they are fabulous -- (Cover Stain or Smart Prime) will cover most anything. I've also used the Sherwin Williams product called PrepRite Pro-Block and was NOT satisfied. I've recently stumbled upon KILZ MAX Primer by Masterchem and it is the bomb ($33/Gallon). Dries fast, little odor, covers completely with no bubbles or bleed-thru, sands nice ... I'm in love. LOL. I've used this product on drywall, stained paneling and an old rustic stained/painted rocking chair and it covered/sealed superbly with one coat. I'm just an amateur but that's my 2cents. A professional will certainly weigh in and give you more informed advice. Good luck! This post was edited by PinesEverywhere on Fri, May 3, 13 at 21:22

Post up a picture of the window if you can. It's likely that you can apply some more tension on the balance system (if it is an adjustable/serviceable type) to hold that upper sash in place more securely.

Sherwin Williams has a product for this and which we used on our former home when re-siding wasn’t in the budget after all the other repairs/improvements we had done. The siding that the previous owners installed in the 80s could not be located or sourced when we fixed windows and other things that had been poorly done (or not done at all) and some had faded, so we ended up with a patchwork of various baby blues (which was bad enough in one shade) and that HAD to be addressed before putting it on the market. Our contractor had done a couple of houses using the SW product and we went to see them and talked to the owners, they all still looked good and the owners had no complaints so we had it done too. It came out great and no one knew it was painted vs new siding and when we sold the house later the next year it still looked good and nothing was peeling, bubbling, flaking, etc. That said, I do think it’s a temporary fix and had we stayed in that house it would have just been a stopgap measure until we did a complete replacement of the old siding.