I tried this and it just gives me an invalid grid data error message after running the calibration toolQuoted from Dartesian in a different thread:
You might try:
Reset any existing calibration in Tablet PC settings.
Press Win key, type "Run"
Copy and paste the following into the Run window:
tabcal lincal novalidate XGridPts=10,60,110,360,660,960,1260,1560,1860,1910 YGridPts=10,60,170,330,490,650,810,970,1020,1070
Run the command, allow permissions, go through the calibration. This makes for near perfect pen accuracy, but it's never going to be perfect. Corners will still be messed up, but that's how it works, apparently. More X and Y points can be added to the lists for even more precision. Each number just corresponds to the X or Y coordinate of a pixel on the screen.
Source: Improved Pen Accuracy with a 100 Point Calibration Grid : Surface
This fixed all my problems I held the stylus normally and it works perfectly in every part of the screen (minor corner issues seem to be unavoidable)