vostro 3559 keyboard automatically typing -------- (dash) key continuously.

Hi, 

I am using dell vostro 3559 laptop. OS: Windows 10.

My laptop keyboard keeps spamming -------- key.Since last 2 days, my keyboard has started typing dash symbol wherever I keep mouse cursor. It goes on typing ---------- continuously. I couldn't able to do my works properly. Is there any solution for this???