Firefox Upgrade

[smoczyna]

Some time ago I downloaded 3.5.2 version of Firefox, in .usr.lib I have 2 versions now, 3.0.14 and 3.5.2. Default version was the previous one. To activate new one I have swapped the star script (actually the link pointing to new version) but after restart of the computer everything returned back to the begininning ???
How to change Firefox version permanently ?