Windows 7

If you don't have a tablet-based PC, you should disable the Windows Tablet PC components and services. These components may interfere with the Wacom Cintiq driver software.

Open the control panel. Select Programs and Features, then Turn Windows features on or off.

Scroll down the list. Deselect Tablet PC Components. Click OK.

(Note: they may be disabled already.)
If prompted to restart the computer, do so now.

If you are a longtime Windows user (as I am, I've been using Windows since version 1.03 in 1987), you've probably developed some deeply-ingrained habits.

On of my most oft-used techniques from the old days: Switching between desktop windows using the Alt+Tab key combination, A.K.A. 'Coolswitch'. Windows 7 and Windows Vista have altered this feature, and not for the better, in my opinion.