What's the model number of the set? It will begin with a "K".
OK, do these lines ever move or are they stationary?
If you press the TV's MENU button (not a cable or satellite menu), do the lines interfere with the menu or is the menu clear?
OK, if this problem also affects the TV's menu and all inputs, then you have a defect in the set's light engine, or optical block, as Sony calls it.
The optical block on this TV is covered by an extended warranty, so you need to contact a Sony authorized service provider and get this taken care of. The warranty is extended through June 30, 2010.
Let me know if you have any other questions, and thanks for using JustAnswer!