KB0011: I want to be able to switch think-cell on or off, depending on which PowerPoint link I am clicking

Answer

The environment variable TCACTIVE, when set, will cause think-cell to be initially enabled (if TCACTIVE=1) or disabled (if TCACTIVE=0), regardless of its last activation state.

Implementation

Go to your Office directory (by default C:\Program Files\Microsoft Office\Office or ...\Office10 or ...\Office11) and create a new text document (right-click → New → Text Document). Put in the following lines:

set tcactive=1
start powerpnt.exe

(If you want think-cell to be disabled, put in 0 instead of 1.)
Rename the created file to end in .bat. Ignore the warning about changing the file name extension. Now create a shortcut pointing to this file (right-click on desktop → New → Shortcut). Now start PowerPoint through this shortcut for think-cell to be initially enabled resp. disabled.