HI,
Re-installing Lightroom will not affect your Catalog you should be able to open it after the install.
The other thing you can try before re-installing Lightroom 5 is to delete your preferences file but it may not make a difference because of the error you are getting.
Look at Preference and other file locations | Lightroom 4 and it will tell you where the lrprefs file is. You can just delete it (if you like rename "Lightroom 5 Preferences.agprefs" to "Lightroom 5 Preferences.agprefs.copy") and try to startLightroom up again.