My screen keeps "looping". starts, goes to black
You can try to get the processor to do a cold start. To do this, unplug the power from the set - turning it off is not enough, you must unplug it!
After 15 minutes, plug the set back in and try to power up. If it works OK, you are good2go!
If that did not work, your set probably has a power supply problem. The best option if it is under warranty is to exchange it.
If your warranty has expired, find a good TV repair shop and ask for an estimate before going any further.