Help menu problems

Since installing Mavericks on a new iMac in February the help menu in all applications has been crashing. Various solutions have been tried with help from AppleCare, but no luck yet. We have trashed caches, repaired permissions,and to no avail. The problem doesn't exist when I set up a new user so it must be a problem somewhere in my Home folder. Any suggestions?

I solved the problem myself after posting my request. I'm feeling quite pleased with myself as an old girl. I went to ~library/preferences/com.apple.helpviewer.plist and trashed it. The Help menu no longer crashes.
Hurrah!