Hello guborr and welcome on Liberkey's forums.
You did not say if Firefox show empty page only when you start it or for every website that you visit, like the Liberkey's homepage.
For the fist possibility go on
Tools\Options. In the
Main tab [b] for startup : When Firefox starts : [b]don't chose : "Show a blank page".
If Firefox does not work for every website, before you reinstal it, backup your bookmarks (
bookmarks\Organize bookmarks... and then in the Library windows chose the
Import and backup button then
Backup or
Export HTML....
Save also the name of your favorite add-ons if necessary to retrieve it easily
after.
You can also have find help concerning Firefox on
Support.Mozilla.com.
JP4U