Laptop LCD problem

Hello,

So I'm having a pretty strange problem with the LCD screen on my Inspiron 5150. I just recently bought an ATI Mobility Radeon 64mb card and it has worked great. A few days ago, though, I was working and all of a sudden the screen turned black. I close the lid and reopened it, and all was back to normal. Unfortunately, that fix doesn't work anymore. Now the screen goes black and nothing will bring it back. I try hitting all the fn + f-key combinations, no dice. All I can do is turn the computer off and wait a few minutes, then the display will come back on reboot. Right now I'm running in safe mode with networking, and I'm not having the problem. I don't think it is a backlight problem, because I can't see any display at all, not even when I shine light directly on the screen. Also, when I adjust the contrast, you can see the black screen getting lighter and darker. I have reseated the cable into the video card and even taken out the video card and put it back in. Nothing seems to work. Could this be a driver problem? The most confusing part to me is that it works fine in safe mode. Any help??