I'm sorry to hear that you're having this issue. Unfortunately, there's not much troubleshooting I can offer to help with this symptom. If it's happening on all inputs, it's likely the TV. If it's just happening on one input, you may want to check your device and reset it.
If that doesn't work, I'd recommend having your unit inspected by a qualified technician. If you need help in finding one in your area, you can call 800-SAMSUNG or fill out the online service request form here:
First time here.....
My Samsung TV works prefectly, except yesterday when I turned it on, right in the middle of my screen are these multi colored lines. Solid, The lines do not move. I do not even know where to start. Please help! THANK YOU
TV Model: LN52A550