Same problem. I've had my N800 for almost a year, and love it. I use it at home many times per day, and have travelled domestically and internationally with it. It's the only piece of hardware which has enthused me for the last 10 years, and I would not be without it.

BUT, starting a couple of weeks ago, the screen has become more and more inaccurate. When navigating small menus, I have to touch almost one full menu line above the item I really want (for items closest to bottom left corner). With the small keyboard, the bottom row chars can only be selected by clicking in their absolute top right corners. Very tricky.

I've recalibrated half a dozen times, and now when I recal, for target 4 (bottom left corner), it rejects my tap, saying "tap closer to target 4". Hey, I'm right on it - but the OS obviously thinks I'm so far off-target that I've gotta be kidding. How do I make it see sense ?