When upgrading drivers on HP TouchSmart tm2 tablet important is to keep in mind that HP Quick Launch Buttons package might disable screen auto-rotation. In order to restore that functionality remove HP Quick Launch Buttons and install older version of that package from here. Full information about package is available on HP Quick Launch Buttons web page availabel here.

Another option might be registry settings adjustment. Parameters which control screen orientation and bahevior are located under:

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Hewlett-Packard\HP Quick Launch Buttons\Schemes\Default\8526

There are two important parameters:
Notebook_Docked_DisplayOrientation = 0
Tablet_UnDocked_DisplayOrientation = 3

Available values for those parameters:
0 – primary landscape
1 – seconday portrait
2 – seconday landscape
3 – primary portrait