my external hard drive fell off of my table and now I cannot open the files.?

Hard discs are super smooth discs, or platters pressed onto a bearing. A tiny arm with an electromagnet in the end causes a magnetic field to be formed which leaves a magnet indentation in the platter's surface. All of this is enclosed in an atmospherically sealed case. A single speck of dust can throw an arm off alignment or scratch data right off platter. Dropping a hard drive is very bad. One of the arms is probably off alignment to where it shows your data but ti will not read your data.

Hard drives are not something that can be pulled open and fixed. Sorry but there isn't much you can do.

reboot, try to see if any file will open

you will probably end up trying to move what you can to a new external harddrive and throwing that old one away

harddrives usually suffer physical damage when dropped and can not be repaired

think about what caused it to fall off the table and prevent it from happening again