It's been awhile since I've posted, but I think this is very worthy of the comeback.
I recently purchased a sweet Samsung 40" lcd TV, the ln40a550 to be exact. I got a great deal on it from Amazon for $929 shipped with white glove delivery.
The first thing I wantedto do was hook it up to my Sony Laptop so I could stream movies from my hard drive.
I followed the instruction in the samsung owners manual to the letter, but the television didn't recognize the PC source.
After reading many posts in multiple forums on this problem I thought i was doomed. This seems to be a specific problem with linking Sony laptops with Samsung TVs.
I messed around with the computer's settings for about 2 hours and finally stumbled on the solution.
FN F7, that's all it is, hold down the function key, and hit the F7 key a couple of times until the monitor icon is highlighted. Then go back to the televison The PC source should now be available for use. Voila! PC on your TV.
I hope this saves someone a ton of time down the road.