Inspiron 580

i bought that        https://produto.mercadolivre.com.br/MLB-693244938-memoria-8gb-ddr3-1333-mhz-pc-kingston-kvr1333d3n98g-_JM?quantity=1          a few days ago, and its not workin, i dont know why, is just doing the classic 4 long beeps, someone help me, if it dont work i have to give back and buy other.