Some of keyboard keys not working on my laptop

Hi i'm using Dell Vostro 5460 laptop and i found out that my E,Q, Caps Lock, and Tab button doesn't work. All the other keys are fine except these. First it was only the E button but suddenly it was like spreading disease that infecting other keys. I'm afraid other keys also got infected in the future. I've been using my laptop for 3 years now so warranty already expired. Do i have to replace the keyboard? or any other solution?. Please help..