I'm sorry to hear that you're having this issue.
I'd recommend having your television inspected by a technician. Unfortunately, I can't diagnose televisions without inspecting them, and a technician would be able to identify and repair the issue.
In the U.S., you can reach them at 800-SAMSUNG.
Purchased LN46A650A1F 12/08.
Yesterday when powering up the unit it ran thru repeated power up / power down sequences (yes complete with "clicking"). Eventually, the set comes on and appears to work normally.
Contacted Samsung via email and despite the fact that they didn't understand the issue, suggested the following:
1. Unplug the set. 2. Push and hold the power up button on the set for 15 seconds. 3. Plug in the set and power up.
After I did this the same issue except the power up / power down ("clicking") occured slower...still came up after a while but this repeted cycling, can't be good.