My name is john and I have a Dell Studio 1555 that has a compound issue with power up, this problem just happened about 2 week ago and I'm just now starting to look into it, here is what it is or is not doing.
With a fully charged battery when you push the power button the machine will not start, it is the same with battery removed and the AC adapter plugged in.
Now through process of elimination I started disconnecting components, CD drive, HDD, Key board and last but not least was the LCD Cable. (after each removed component the power button was pressed and no go) until the LCD cable was unplugged. I then performed a hard shut down, re-connected the key board, HDD and CD drive and the LCD cable and nothing, removed the LCD cable and plugged in external monitor and hit the power button and the computer will boot up in safe mode.
Once I try to boot normal it will go through the post boot and then it will go black on me. If I go back into safe mode and delete the current display drivers and let it boot up it will work fine until I update the display drivers then I'm back to only having a display in safe mode. Once the LCD cable was disconnected the computer would give 8 beeps (which is LCD Failure), so I disconnected the cable from the monitor itself and plugged it into the mother board and once again not startup, I disconnect the cable and it will start. SO is the cable it self bad or is it the motherboard going bad?