My TV wont work (makes me sadface)?

ok. so i have a Samsung TV (i know there are a lot of problems with them) that i have had for about 3 years now. a few days ago it just stopped working right. i turn it on and i will hear the voice of the channel im on for about a second and then it will turn itself back off. any suggestions on what to do? (please nothing stupid like "Hit it with a sledge hammer" or "Shoot it" serious suggestions only)