Sam,
I have windows xp sp2 and I am unable to open chm files, I get a
message "cannot open the file: mk
msitstore:c:\...."
Here are some things to try:
1) Use MJ's Help Diagnostics to check that all the help viewer
components 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) Delete or rename the file hh.dat, which you should find in this
hidden subdirectory:
\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, search history, 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 succeed in opening a help
file.
3) Empty your Temporary Internet Files directory (in Internet
Explorer, Tools > Internet Options > General tab > Delete Files). A
full TIF directory can cause the help files to misbehave.
4) See the following page for further guidance on how to resolve
XP-specific help problems:
http://www.kellys-korner-xp.com/xp_h.htm