HP Monitor on for 5 secs

Hello,
I need help fixing my home computer it was working fie yesterday and today it was flashing. After, the flashing the screen went black. So i decided to turn it back on and it did but only for 5 seconds. I'm not a computer expect but i know some stuff. The flashing was only bright then normal then dark then off so if you can send me an email to help me it would be perfect. You can reach me at dozer.v5900@gmail.com