I have a Latitude e5540 that doesn't turn on (at least not easily). But when it does turn on, it can stay on for weeks/months as long as it stays in sleep mode. This has happened three times now. If I shut down or reboot the computer, it doesn't turn on again -- or at least it's very difficult to get it on and it seems to randomly correct itself and turn back on.
Here are the symptoms when it doesn't boot up:
Troubleshooting so far with no noticeable difference:
I'm running out of ideas. I found diagnostic light information somewhere but it doesn't say anything about just a solid white power light with nothing on screen.
Any troubleshooting tips?