For some strange reason, my IPad's (gen1) screen rotation is frozen in the horizontal position. Nothing I can do will afford it's vertical viewing position to me, now. I don't know what's caused it, but it just happened a few minutes ago. I've made certain that nothing had been, inadvertently, changed in the 'General Settings' area (where screen position locking could be held by the sliding switch button, on the side of the unit). Absolutely nothing has been done any differently than before.