When you push on the power button, the power light on the laptop turns on but the screen shows no image. The laptop screen remains black and blank. Video on the external monitor also not working even though it used to work fine before.
1. Memory failure.
2. Video card failure.
3. Motherboard failure.
Possible troubleshooting steps and repair solution:
1. Try reconnecting memory modules, maybe one of them is not making good contact with the memory slot.
Try removing memory modules one by one. Maybe one of the memory modules is bad. The laptop might start properly when the faulty memory module is removed.
If you have only one memory module, try moving it to another slot. Maybe the slot itself is bad.
Try replacing memory module with another known good module.
2. If you have a discrete video card, which is not common, there could be a problem with the video card.
First, try reconnecting the video card to the motherboard. Maybe connection between the video card and motherboard is bad.
If reconnecting the video card doesn’t help, try replacing it.
3. In most newer laptops the video card integrated into the motherboard. If the video card fails, you’ll have to replace the motherboard.
If playing with memory modules (as explained in step 1) didn’t help, most likely there is a problem with the motherboard and it has to be replaced.