save a copy of your db files and install 1.7.17 as you would if it were a fresh install.
Please read changes and changes.conf for information that you would need to add/change.
If you suffered from data loss during a previous upgrade, then it's most likely from something other than the upgrade. 1.6 and 1.7 db file formats are the same, meaning you can upgrade from 1.6 to 1.7 and still use the same db files.