Why doesnt whattsapp work on my asha 501

Why doesnt whattsapp work on my asha 501

after updating my fone nothing works, i've reset it but cant retrieve my default apps and settings, i've search alot for help on the internet, only 1 answer were making sence but with the package i did not recieve a software disc with the purchace of my fone. how can i manually restore the firmware on my fone. thank u. email me on wernereiman@gmail.com