John & Penny:
In the 06 Mtn. Aire we had, the slide up window screens were removed by first raising the glass portion of the window, then lifting the slide up screen a few inches and grabbing the lower edge of the screen with one hand and the upper edge with the other hand and applying steady, but firm pressure
toward one end, (or the other) of the screen you're holding.
Explanation:There are plastic spring clips located along
one of the short edges of these screens which ride in the vertical track and ya need to firmly compress these plastic spring clips while slipping the
non-spring clip end out of the track. YOU have to figure out which end of the screen has the spring clips in side the track. Only one end has the clips since the other end needs to pop out of it's side of the track. Hope this helps. Don't twist the screen frame while doing this...try to apply firm pressure in a straight lateral direction, or ya might break those curved, plastic corner pieces used on the lower margin of these screens. By the way, ya maybe CAN fix this if ya break one, or ya CAN order these curved plastic corners from Newmar....(guess how I know this

).
Steve