Problem after upgrade to Joomla 2.5

Is it possible that after upgrade to joomla 2.5 all menu and links don't work ? what can i do now ? http://www.borntogolf.it

The News template is no longer supported by gavick. You would need to make changes to the template files to make it compliant with J1.6-J2.5.

Here is somewhere to start http://docs.joomla.org/Upgrading_a_Joomla_1.5_template_to_Joomla_1.6 Modules and php files will also require attention.

It might be easier to restyle one of the later news templates to match your current design. You would also gain support and framework improvements/development in the long term.