Thank you gibbs1984 and Rush Lindsay
I just use normal messages like others.
All this problem maybe happend when i open whatsapp,then suddenly the screen black. then maybe 5 second laters back to normal.
I already uninstalling that app and remove and reinsert the battery, but still can't open messages. i try to [Settings - Applications - Messaging] but not sure because mine show [Setting- application manager= then show the downloaded app]