My old XPS m1530 ccfl backlight turns off after 1 second when I open my laptop. If I close it and open again, it works for 1 second and turns off again. I belive it has something to do with sensor that assumes that laptop is closed and turns light off. It has nothing todo with OS since this issue is reproduced even with HDD removed and during POST.
There is no warranty because I got my laptop in 2007 (time to upgrade probably, but there is probably some way to fix it?