I had this problem on my Ferrari 4005. It took about 2 days to dissapear, but i was using the computer during that time.
BTW, WarcraftIII can cause this to happen over a period of about 30 minutes if you leave it paused.
I left my F4005 in the menu while playing warcraft III last night (F10 key) for about 45 minutes.
I noticed that I had what seemed like screen burn on the LCD so I shut down the laptop overnight thinking that it would disappear. Well, it is still here today, and quite annoying.
Anyone else have this problem? (Search isn't working for me at the moment.)