When I try to open CHM file on Windows XP or Windows Vista, it always display a message “Navigation to the Webpage has been canceled.”.
Finally I have worked out how to resolve this problem.
Right click on the .CHM file Click on “Properties“ then choose the “General” Tab At the bottom of that tab, you will see something like
Click on the "Unblock "button which is beside to this message.
You should be able to view that CHM.File now