I have almost 3 years old Dell XPS M1530 laptop that's been very reliable until couple of weeks ago when the display started to act weird. When I turned on the computer, the screen went blank not even DELL logo page. Windows started normally since I heard start-up sound but no display. When I restarted the computer, no Dell logo page, but Windows screen appeared with lowest brightness. Also, I could not adjust brightness with fn+arrow up key. When I restarted the computer third time, Dell logo appeared and the display functioned normally. This symptom lasted for about 3 days. I cleaned heat sink and made sure that the heat sink and video chip was in good contact as it was recommended by Dell forum. Everything seemed working fine since then but 3 days ago the problem started again. This time, no Dell logo but Windows screen appeared with lowest brightness and fn+arrow key did not work at all. However, if I restart the computer DELL logo appears and everything is fine. The problem occurs only when I start the computer after completely turn off the computer. When I restart the computer everything works normally. Does anybody have same or similar problem as I do and if you do, do you have any idea what might be the problem? My concern is that if I keep using the laptop this way, things might get worse and end up replacing motherboard or entire display. Thanks for your reply in advance and hope any of you may have some ideas as to how to address this problem. My laptop's specs are following:

Dell XPS M1530


4.GB Ram

NVIDIA GeForce 8600M GT

Windows Vista 32