Certain Keyboard Keys Not Working

My keyboard, on my Dell Inspiron 13 inch 7000 Inspiron isn't working properly. It was working fine not too long ago, but, now some of the keys aren't working all the time. Most of the time certain keys don't work. Which are: delete, backspace, play/pause, FF, RW, Brightness Down, Down arrow key, up arrow key, left/right arrow keys. Sometimes these keys work, sometimes they don't. There's no pattern of when they work or when they don't. Sometimes they work in Chrome and sometimes they work in Microsoft Office programs. But, sometimes they don't. I haven't dropped anything so I don't why they stopped working. They all worked before and now they randomly stopped working. I have not installed any new programs, or uninstalled any. 

Please help me, thanks.