Why does my computer shut down randomly?

Hi, I've looked at the post people have made to this problem and none have answered my problem. My laptop is not overheating and there is no dust in the fan and the battery is fine. It seem to shut down just totally randomly and when I try to turn it back on right away it shuts down right away within the first 5 minutes.

Please help I need this laptop to do school work and is very frustrating when I'm trying to complete a project.

Thank you in advance.