In windows, reinstalling the OS is often the best, sometimes the only solution. With Linux, you have total access to the system. Things can be fixed.
For problems with Libre Office, the best way to get some clues is to launch it from a terminal. Use the command -
or whichever version you are running, if not 3.4. If there is a problem, there will be terminal feedback.
A second method is to run lomanager from the terminal and choose a reinstall of Libre Office. If there is a problem, there will be terminal feedback. Or it will be reinstalled, with terminal feedback likely.
The point is that it is possible to discover and fix problems. A reinstall of the OS is a "last resort" fix, not first. First resort is to gather all the information you can and post here to ask for help. The more information, the better. Then people here can help you to find and fix the problem.