accord 2004 satnav screen intermittant?

hi any body had this problem my sat nav screen sometimes works sometimes wont you can see screen trying to load but stays blank. also the screen wont show up the radio settings or a/c settings either if sat nav works then everything else works. if i have sat nav working on acc and start engine screen goes blank and will not work untill i have removed key and started all over again any help would be appreciated