I'm sorry to hear that you're having this issue.
If the unit is out of warranty, you can still call 800-SAMSUNG and have a technician dispatched; however, the cost for any inspection and repairs will be at your expense if it's not an issue that qualifies for an additional coverage.
I bought a similar TV to the one above at Circuit City in late 2008. Within a week, we started having the same problem you find in complaints re: the TV won't turn on, etc. and Circuit City replaced the unit. We have begun experiencing problems with what others on the net refer to as a "side shadow." Sometimes it works itself out, but sometimes we just can't watch the TV because it encompasses more than half of the screen. It's a blacked out portion of the screen, but some of the picture sometimes shows through, at times upside down. What can be done for this issue? Of COURSE, the TV is no longer under the 1 year warranty I made SURE to sign up for. Thank you.