Sat nav dead Clio RS

My sat nav has recently gone down in my 63 plate Clio RS Cup model. stating ‘no maps found.’( Tried, re booting, taking SD card out & leaving, disconnecting from battery etc- nothing.) Prior to this, my alarm had been going off throughout the day on & off for no reason?! Sensors were checked, no faults were found.Were they linked? Now, satnav dead, alarm stopped!! Garage advice, ‘needle in a haystack?’ I can’t be the only one? It’s an R link. Can anyone advise please?
 
In 197 and 200 models a faulty battery or dodgy earth could cause lots of problems with alarms going off. Have you tried changing the battery?
 
My battery is quite new. The thing that is unusual is that my entertainment system is still working. It’s only the Navigation part on the menu that’s ’greyed’ out & showing up ‘no maps found.’