How To Fix My TV That Turns Off When I Press The Power Button?

Sounds like the safety fuse in it is shutting it down, like a surge protector. We had a t.v. Do this to us one time, it wasn't that expensive to have fixed. You might do the same. Hope this helps, good luck to you.

Tiggers answer is one possibility I would also suggest you consider it may be a loose connection or broken solder.

Do you have any other appliances in the same socket or extension just to ensure it is the TV itself and not the power supply?

If it does have a safety fuse fitted then check your manual, there will no doubt be a panel yopu can remove to change this yourself, just make sure you put the right one back in.

How do i fix my tv that turns off by its self.

My tv will turn on but when i move it a little it will go off.if i hit it slow it will turn on