Good afternoon. After a fall, the most logical thing is to think that some component has been released or has been poorly connected. It could be solved by opening the computer and if at first glance it is not appreciated which component is badly connected, then it would have to go through everything. As it is a portable and surely it is not easy or comfortable to tinker so thoroughly, I would only try to remove the module or memory modules and the hard disk and reconnect them, with the equipment completely disconnected from power and with the battery removed, of course. There are times that after an accident like this, repositioning these two components is resolved. If not, then you have to thoroughly check inside until you find the problem. I do not recommend anyone without experience to open a laptop, it may be its end, but in many models it is simple to disconnect memory and hard drive.