If you are using TAS, the Terrain Analysis System on Windows 7, the Help function does not work. To fix it:
1. Close TAS
2. Open a command prompt as Administrator and type:
regsvr32 /u /s richtx32.ocx regsvr32 /s <Path to TAS files>\richtx32.ocx
regsvr32 /u /s richtx32.ocx regsvr32 /s "%PROGRAMFILES%\TAS209\richtx32.ocx"
3. Open TAS and see if the Help function works now.
By the way, TAS is not under development anymore and the developers have moved on to the Whitebox Geospatial Analysis Tools.