If you have installed Annotate (either the free version or PRO) and can see the new buttons/toolbar, but clicking the buttons doesn't seem to have any effect, try the following:

All users:

• Restart your computer and run Microsoft Word again

• Click the Office button (top left of the screen) in Word, then choose Add-Ins.
  
  • Do you see Annotate listed? Click 'Go' at the bottom of the screen to see the list of current add-ins. Select Annotate and click 'Remove'.
• Use add/remove programs to uninstall Annotate (not .NET)
• Download the .zip file again (sometimes the files are corrupted during download)
• Reinstall Annotate