Today we went out to the farm. It's hot (mid 90's, heat index over 100), so we couldn't do much. But the other day when we had the foundation fixed, the guy told me that all the windows should open just fine now. We tried to open one and it was a little tight. He said that wasn't because they were out of square but because they were just dried out and the springs weren't lubricated enough.
I tried using soap, I've heard that's a great way to lubricate sliding mechanisms, but because these windows are metal framed, and have built in springs, we needed something that would penetrate the tight springs. Of course my first thought was the old standby WD-40. So I did a little online research and found that something called "PB Blaster" works wonders in penetrating stuck bolts and screws, so I thought, that might work best for getting down inside the springs of the window.
So we stopped off at the store on the way out there and picked up the can you see above.
When we got to the house, we tried opening all the windows. Some opened a little easier than others, but none were really easy to open, they all took two hands to lift them.
I started in the living room, sprayed down the the upper tracks, while the windows were closed, and then squirted it down into the lower sections. We unlatched them, lifted and closed them a few times to make sure it was throughout the tracks, and voila!

We have windows that you can literally open and close with one finger. The PB stuff works wonders and it states on the label that it doesn't evaporate so it should stay in there for a long time to come. Only two downsides I noticed. One, the smell, it's pretty strong. I thought it smelled like Kerosene, 2nd Man thought it smelled like bug spray. Either way I'd use in a well ventilated area. We opened all the windows after they were lubricated, and then went down to visit 2nd Family at the other end of the property and before we left, we went back up and closed them all. The smell was gone, it had aired out completely. The other complaint was the lack of a tube (like that "other" brand) that would direct the spray in one concentrated area. We managed OK, but it would have been a tad bit easier with a tube.
We're fortunate, Ma had all of the windows in the house replaced about 10 years ago, so they are still new and fully functioning.
The house has a total of 17 windows, 15 large of the same size and 2 smaller ones. That will certainly make measuring for curtains, blinds, shades, and other window treatments very easy.