Tv turning itself off?

Hi

This TV was bought about 4 years ago and I cannot find it online to trouble shoot so wondered if you can help us.

When you switch it on it appears to turn on (green light comes on and there is a static flicker), but seconds later it turns itself off as if it is in standby mode.

Is this a common problem, and is it worth fixing?

Thanks for your help.

Nikki