CR240E Won't Boot

At the beginning of October I had what the common folk might call a "berserker rage attack" and hit the bottom of the laptop with the battery about 6 or 7 times. This resulted in several cracks appearing on the paneling. I assumed all I had done to it was superficial damage, so I unscrewed the panel in-question and smoothed out the cracks.

However, when I attempted to start the computer, it wouldn't boot up. It turns on, which triggers the typical thrumming sound, but nothing else happens. The battery holds a charge just fine, so it isn't that (it also doesn't boot up when I take the battery out, with the computer directly dependent on the outlet). And it's not the RAM cards knocked loose, as that's the first thing the repair guys checked.

At first, they said it was probably the hard drive, that when it was damaged (I told them I dropped it) some kind of spindle or wire or needle thing was jarred loose so now it doesn't work anymore. However, when they put in a replacement hard drive it still didn't work. So now they say it's the motherboard, and I might as well get a new computer. However, I've had a kind of runaround with this place before, so when they say it's the motherboard they can't be 100% sure that that is the actual problem. And unfortunately I live in a small town, and this is the only repair shop for over 300 miles.

I guess my question is this: is it the motherboard that has failed, or is it something else that is wrong, something that is more easily fixable. Is there any way that I can find out it is solely the motherboard that is damaged, beyond a shadow of a doubt?

Because I've found a replacement motherboard for around $150, and I can get it installed for about $80. But before I do that, I want to make sure that it is actually the motherboard , and there won't be any additional costs.


So... any advice, really, would be appreciated. Hopefully I didn't get to carried away and longwinded.