I'm not very savvy when it comes to laptops. I have two identical laptops, old school Dell Latitude D410's. One works just fine, and the other does not boot at all. I have tried various things including, using the working battery pack and power adapter from the running computer. Swapped out the hard drive from the working computer to the non-booting laptop. Nothing seems to work. I really don't have a clue as to what it could be. But it does absolutely nothing. No attempt to boot, no sounds, no lights, etc. Any ideas?
Not savy? Sounds like you tried all the right stuff and reported the critical info. Apparently you've attached a verified working battery and/or power supply and no lights were on. That's an indication that points to a bad motherboard. At that point in your testing, if you had a bad hard drive or memory or missing OS, you would have at least gotten the laptop's power LED to blink or one step better, beeps or blinking diagnositc leds. When you don't get any of those, with available power, then somethings wrong with the motherboard.