All Mac user account deleted
Hi
I was taking my MacBook out of my backpack one day and it fell on the floor. It was a wood floor. The MacBook did not seem damaged aside from same marks and scratches. My real problem was that when i went to log into the computer, it would not let me log in. It denied my username and password (i had the setting where i would enter a username and a password at the login screen) as if the account did not exist. My computer was turned on and in sleep mode when i dropped it, so when i opened the laptop it asked for the password which was denied. I then powered off the computer and tuned it back on (everything seemed to be normal except the color of the screen was different, no problems though). Since my account was not working, i was able to login with the guest account. I was able to change the color of the screen back to "color lcd". When i went into the user and group section in the system preferences, NO user accounts showed up in the list. I am only on a guest account so i cannot make any change like making a new admin account. So there is no admin account on this anymore, only the guest. I know how to reinstall the OS, and most of my file are backed up, but i am wonder why and how this could happen and if there is a way to fix it.
PS. My user account folder with my files is still there, i just have no way of accessing it.
Thanks,
Michael
MacBook, OS X Mavericks (10.9.5), white, mid-2010