Why is my phone cannot be on?
Nothing appears on the screen except the word OPPO.
I switch off the phone and restart but only the word OPPO appears.
What should I do?
Your phone might have bootloop caused by software problem and it could be solve by hard reset. Hold volume up and power button at same time until screen shows oppo and small recovery mode text below. Just follow the wizard on screen to reset aka format and wipe cache so on.
There are also way to reset using pc and you can find tutorial on how to do that googling oppo hard reset or unbrick oppo. Mine has same problem too but it cannot enter recovery mode or recognized by pc. So just waiting for expert help on this