I was searching about the information regarding difference between online help and user guide .
I have summarized the huge information I got related to it. I think it provides the crux of the matter.
Online Help:Online help is nonlinear and precise. It is context sensitive and provides hyperlinks, unlike user guide. It can be updated. It is a form of user assistance. It is created by using help authoring tools. There are many tools like, Robohelp, HTML Help, etc.
User guide has to be linear and elaborate. It includes screen shots or images.