|" Is there a chance I will be able to see the damage if I remove the mboard?"|
According to my experiences, that's very unlikely.
When I said ...
"the damage to one corner of the mboard was obvious"
....I.should have stated the mboard was physically damaged there. I had not taken it apart previously since it worked fine with an external monitor - it was probably the same physical damage it originally had after it was dropped.
I used good lighting and a magnifying glass to examine everything inside the case and found no obvious damage otherwise.
I've done that many times when something had failed, out of curiosity - a card, power supply, mboard. Other than possibly failing (bulged tops, evidence that shows fluid has leaked out) or missing (it blew up) electrolytic capacitors there's usually nothing obvious.( I did discover power supplies rarely blow the fuse they're required to have.)
Rarely, I've heard, the mboard has a fuse device that blows when it experiences a short, but it doesn't necessarily blow depending on what event happened, it usually doesn't look like what you would expect it to look like, and I've only heard of that for on desktop mboards. I've never seen that on a defective or dead mboard myself, but I'm not a technician who works repairing computers all the time and I haven't seen a lot of them.
Two of the USB ports were on a power card that plugs into the mboard - the same one that has the jack the AC adapter plugs into - but there is a third USB port on the mboard and that doesn't work either. The battery still charges fine. The keyboard had not been abused. When the USB ports were working previously, a USB keyboard worked fine even during booting.
I could probably find a replacement mboard, but I don't want to replace that and then have to replace the display assembly too. I could get a working equivalent used laptop for that total amount of money or less.It is recent enough that it has Vista on it. The friend has Parkinson's (he's only about 55) and has only a government supplied disability income so he chose not to bother trying to fix it.