Installing Frostwire 5 should not have actually removed Frostwire 4. if you installed it in the normal way as an upgrade. However installing version 5.0.8 will remove 5.0.7 if it is installed.
When you install Frostwire or any other program afresh you need to go through the installation process and the pages that show for this are collectively called the Installation Wizard.
OK lets try the other way of totally uninstalling Frostwire4 and 5 and making a clean install:
Completely remove all traces of Java and Frostwire. To do this use Revo Uninstaller
or a similar program since Windows uninstaller in the Control Panel fails to do the job thoroughly. Revo will locate additional related files which need to be removed.
Before doing this ensure you have a back up of the files in your save and shared folders, or at least remove them to your desktop or somewhere similar, just to be on the safe side.
Then install Java from HERE
using the offline installer and finally Frostwire from the FrostWire.com link above.