You really do need to run a full clean install to avoid importing any "baggage" into your new installation. Just copy all data to some external storage media before installing. This is one of the many reasons why I recommend partition your drive into at least two partitions. The first to hold op sys, apps and associated configuration files, drivers etc. The second to store all user data files - avoid saving any user data in the system drive. This way, when you need to reinstall you do not have massive problems backing up and recovering data.