I have a Dell N5010 laptop. I recently got my motherboard changed from a local repair shop. Ever since I started using the new motherboard, it so happens that every other day when I switch on the laptop, it boots into a black screen. Even, the Dell logo at BIOS boot doesn't show up. The screen remains completely black as it was before the laptop was turned on. But the OS boots up properly and by hearing the sounds that Windows 7 produces at Welcome screen, I can say that the OS has no problem. Also, after the Welcome screen, I am able to use Windows freely (by using Windows narrator), the only problem being that the laptop screen remains pitch black.
But, the blackout phenomenon is not consistent. Sometimes, when I turn on the laptop, it boots up fine with screen display right from the bootup time. Sometimes, the blackout continues till the Windows login screen, and then screen lights up. It is noteworthy that once the screen starts to display it continues to do so for hours without any problem.
I tried to troubleshoot the problem. Once when the laptop booted up with a black screen, I attached an external monitor to the laptop. Nothing came up on the external monitor as my display was
computer-only. Then I pressed the F1 key two times, so that the display shifts to
duplicate. Though, my laptop screen remained black but the external monitor displayed my Windows desktop and I could do everything perfectly.
Another observation is that if the laptop screen is lighted up, some software events can make it go black. For example: once I pressed '
Switch User' button in Windows to go from one user account to other. This caused the screen to blackout. Then I typed the password of the account and pressed Enter which logged me into another account and also caused the screen to light back.
Once when the screen was black I tried to install the video driver (I have ATI AMD radeon Hd 4650 video card) using an external monitor to guide me through the process. While doing the installation the screen of laptop lighted up for about 5-7 seconds but again went balck.
According to me, the problem can't be software-related because the screen is black even before the boot up. But it can't be hardware-related either because once the screen lights up, it doesn't go black unless some software events happen. In short, I can't come to a conclusion.
Can anybody tell me what the problem can be? Thanks in advance.