Looking for help or advice please. I have had my TV for less than 2 years. On Sunday it was working fine then all of a sudden a dark mark appeared across the majority of the screen and it started switching itself on and off. I can no longer see what I am pressing with the remote, but the TV is still responsive to the remote. Also has sound. When it comes on it stays in for about 10 seconds and switches itself off again and repeats unless I switch off at the wall. Every now and then the full screen works and looks like normal. I managed to do a factory reset, but now getting the same issue in the startup screen. Any suggestions? Also out of the Samsung warranty and wished I had done more research before buying a Samsung TV. Thanks in advance!