JR,
None of my help files (*.chm) will open when I double
click on them.
Here are some things to try:
1) Use MJ's Help Diagnostics to check that all the components used to
display HTML Help files are properly installed and registered.
http://helpware.net/downloads/index.htm#MJs
(The only section of the MJ's Help Report that is relevant to your
problem is the one headed "HTML Help Run-time Components".)
2) Use Microsoft Critical Update 811630 to upgrade the HTML Help
viewer components. This is available from here:
http://support.microsoft.com/?kbid=811630
3) Delete the file hh.dat, which you should find in this directory:
\Documents and Settings\%username%\Application Data\Microsoft\HTML
Help
The hh.dat file stores user-specific information on all the HTML Help
files on your system (favourite topics, changes that you've made to
the size and position of a help window, etc.), and can cause the files
to misbehave if it has somehow been corrupted. Windows will create a
new version of hh.dat when you next open any .chm file.
4) Empty your Temporary Internet Files directory. A full TIF directory
can cause HTML Help files to misbehave.