Hi guys.. am using nokia 5130 for past two years.. it gave me ample amount of problems..?

but for the past 5 months.. it was working properly.. rite from day b4 yesterday.. its getting restarted on its own.. settings gets changed.. but now.. music player is not working.. if i enter it.. it just says.. NOT ENOUGH MEMORY.. what does it mean.. why is it happening like this.. what should i do