To quickly rename multiple files in the same directory:

1) Open the folder you want and select all the files you want to rename.(Hold Ctrl and click each one).
2) Press F2 and it will allow you to change the name
3) Enter the prefix you want for the names of all the files you are changing.
4) Hit enter, and after doing this you will see that it automatically renames the rest of the files with the same prefix for you (Ex: Newname(1).jpg, Newname(2).mov, etc.).