Help Explorer Viewer is a full-featured help viewer for both Windows and Linux. One of its main advantages is 100% support of the WinHelp (.hlp), MS HTML Help 1.x (.chm) and MS Help 2.0 (.HxS) help file formats that are widely used in Windows.
Help Explorer Server is a web-based application designed for viewing compiled help files in different formats: Microsoft Windows Help (WinHelp) - .HLP, Microsoft HTML Help 1.x - .CHM, and Microsoft Help 2.0 - .HXS.