Help file generator / online demo recommendations

Hello all,

Just wanted to ask if anyone had any recommendations for help file writer's
/ generators? I used to use WinHelpPro, and I'm now looking for a good
program for creating and generating the more modern help files.

Also, I used to use Viewlets for creating online demo's. This used to be a
free product, but I don't believe it is any longer. Anyone know of a good
free resource for this?

Many thanks,

Andy