Hi @naominyawira
Try to get into the recovery menu by pressing and holding the ''Power button'' + the ''Volume Up button'' (both together)
When the Freeyond logo appears on the screen, release the Power button but still hold the Volume Up button operated, until the menus appear.
If you get into the recovery menus OK first try the ''Reboot system now'' option and see if that works. Use the volume buttons to step through the options and then press the Power button to select the option and then follow the prompts.
If still no good then you may have to try the ''Wipe data/factory reset'' option.
''***Be aware*** that if you try this option that all your ***personal data and downloaded apps will be erased*** from the phone. The phone will be reset to its factory default condition. Like it was when you first got it. Also if there is Google account tied to the phone you will have to know the account user name and password to access the phone to set it up again after the reset has been completed.''
If still no good after performing a factory reset it may be a hardware problem and further testing would be required to find out what's wrong.