We have a Samsung model HLN5065w1x/xaa 50 inch DLP. It will come on with sound and no picture and cannot be turned off with the remote or off button. After about 2 minutes it will cut off by itself. Then in about 2 minutes it will come back on with sound and no picture like the first time, and after about 30 seconds it cuts off by itself and stays off. The set is approximately 5 years old. Is this TV fixable and if so what do you think the problem is and can I order the part online? Thanks for your help.