My phone is not booting up, the red light stays on, but still not switching on. How can I fix this?

[AC Question]

my phone is not booting up. the red light stays on, but still not switching on

The phone was 50% charged. As I wanted to use it, it just switched off, and now the red light stays on, but the phone is not booting up.

 

[nahoku]

How old is the phone? What kind of phone? You could try holding the power button continuously until you see something happen. Plug it in first.