My CF-30Mk1 ts was spot on for months. Last week, while using the unit, the calibration went out about 1" to the northeast of where the stylus touched. Tried to calibrate it using the 'Tablet Calibration' app in the control panel, but the results were the same as before. If I used the 'Calibrate' app in the 'Tablet PC Settings' in the control panel, the stylus was not recognized by the second cross-hair, so no calibration.
I installed an ssd and put Mint 15 Xfce on it. Calibrated perfect. Put the W7 ssd back in and nothing had changed.
After talking with Sadlmkr for about 20 min, he asked if I had tried the 'Reset' button in the 'Tablet PC Settings' app. I said no but that I would try it. Clicked the button, answered yes to the dialog box asking if I wanted to reset the calibration and that was it. Stylus was spot on again. Didn't even have to calibrate the screen.
So if your screen suddenly goes out of calibration, try the reset button first. FYI.
![:D :D](./images/smilies/biggrin.gif)