Hello!
Android devices needs restart from time to time. Some apps are heavy for old phones/tablets and this makes them "freez". Don't panic
the tablet is working fine (or there is another problem?). Restart it from time to time and you will be fine. Try to clean the tablet! You may use apps like Clean Master or simular
Regards,
GeRgY
p.s. Just to inform ... i made some changes of your post