BleepingComputer.com: Gateway 6510gz Laptop Not Powering Up

I am working on a friend's GTW 6510GZ. I haven't got the computer in hand right now, but here are the symptoms as described to me.

*One and one-half mos. ago the computer was dropped, but by some miracle it kept working.
*About one month ago, the computer was not powering up. A repair shop replaced the power cord and it worked fine after that.
*Last night, the computer stopped working while it was running on battery power. Everything went dark and powered down. Now, the charging light does not turn on when it is plugged in, and the computer does not power up on either of its two batteries. The batteries have built-in testers that indicate that there should be enough juice in them to run the computer.

Additional information: When the computer went down last night, it was not on someone's lap, and it was not being handled by anyone. The power cord fits snugly in the power jack, and the jack does not wiggle, so I do not think that it has broken from its moorings.

Any leads, ideas, or things to try would be appreciated. I am not a professional, but I am usually able to fix my own computers. Please, if you use obscure technical language, spell it out for me. Thanks for reading this!

It may be that the reading head on the hard drive was damaged or shaken loose by the fall and it did not show symptoms until lately. I think the only way to prove this without running a professional diagnostic on the system would be to remove the hard drive from another person's laptop (they should all be 2.5") that has the same interface as your laptop's hard drive, and then plug it in and see if it works in yours. If that one works, then the HDD is at fault. If not, I'd say some important part is irreparably damaged and needs to be replaced.