Hello HILMAR11 and welcome to the RH community.
Before you do anything, take a backup of your project and
store it somewhere safe just in case...
Now are you saying you want to use the RH for HTML
application rather than the RH for Word application? If so, try
opening the application and creating a new project. As part of that
process you have the option of importing files. There are various
options but try either an .rtf or hlp file. You can even try your
RH for Word project file. Give them a go and see the
results.