Question: My system has no .CHM viewing ability. When i launch a .chm file i either get an application error from the program it relates to, or nothing happens. I believe it has something to do with C:\WINDOWS\hh.exe. Any ideas ?
Answer: One of these suggestions might help.
Clear the Temporary Internet Files
1. Close all Internet Explorer windows.
2. Type INETCPL.CPL in Start, Run dialog
3. Click the Delete Files button
4. Select Delete all offline content and click OK
5. Click OK to close the dialog
Clear the contents of the TEMP folder
Type %TEMP% in Start, Run dialog. Select all files in the Temp folder and delete them. Some files in the TEMP folder may be in use. If so, ignore the error and continue deleting the remaining files in that folder.
Register the core modules using these commands
regsvr32 mshtml.dll /i
And another step, suggested by Pete Lees [MVP]
You could try deleting the file hh.dat, which should be in this directory:
%userprofile%\Application Data\Microsoft\HTML Help
Hh.dat is a database file that saves such session information as the window position and favorites for the HTML Help viewer. The database file is automatically updated every time the HTML Help Viewer is used. If the database file does not exist, it is re-created. When updating the HTML Help viewer, the information in Hh.dat is not necessarily compatible with the new viewer, which can cause it to become corrupt.
PRB: HTML Help Viewer Causes Access Violation
PRB: Hh.exe Causes an Access Violation When Opening .chm Files
Reboot, and then try opening a CHM file to test.
Type in Start, Run: %Windir%\Help\access.chm