When install of help module for Ver 3.6 An error of 1714 causes a failure. It is looking for a prior install msi for ver 3.5.5 which I do not have
Microsoft Installer error 1714 is result of a missing or corrupt installer package.
Since you are having problem uninstalling the Help pack, guess you must have made the common mistake of removing LibreOffice 3.5.5 before the Help pack. Sequence going on is: LO then Help pack; and coming off is reverse: Help pack then LO.
And for stability during release upgrades, any 3rd party extensions would go on last, and come off first.
So two choices, you can manually complete an uninstall–of program files, component objects (registry) and configuration data (registry and file system). A little tedious but very possible.
The other choice, simpler, is to complete a reinstallation using the LO 3.5.5 and Help pack installers–to reestablish all components. And then run the uninstallers (use add/remove programs) in the correct sequence. When finished, clear the left over per-user configuration from the C:\Users<username>\AppData\LibreOffice folder. Reboot, and start a fresh installation with the current 3.6 installers.
You can download archived versions of the LO and Help pack installers from this Document Foundation maintained site, navigate down into the version and OS you need:
http://downloadarchive.documentfoundation.org/libreoffice/old/
On my Windows 8.1 system LibreOffice_4.3.3_Win_x86.msi is needed to reinstall a newer version, but it can´t be found on Index of /libreoffice/old. Using Wise Registry cleaner did not help clearing the garbage. Where can i find a complete list of all component objects (registry) and configuration data (registry and file system) to remove them manually?
I think it is a bug of an uninstaller, not a mistake of a user to remove software, if there are unmet requirements. If other software has to been removed first - the install program should know this and inform the user about this fact and the possibilities.