I recently received a DELL Latitude D610. It won't power up. The 3 lock-looking lights on come on for a second or two then the machine turns off. It does this with or with out the battery. The AC adapter light is green when plugged in.
If you tried another power adapter, probably. Unless the battery is fully dead and the charger port on the laptop is also bad.
Sometimes a bios reset may fix things, rare though for that to work, but I have gotten some laptops working at least for a bit by doing that. Need to pull the CMOS battery for 15 or so seconds with the power and battery out.