goku defeated frieza and frieza got mad he tried to blast goku but goku blasted something stronger and destroied planet namek after king cold who is friezas and coolers dad was in his space ship and...
yes his death ball destroyed bardock and the rest of the sayins except the few he let live nappa,vageta,raditzand goku in which he didnt know about because he was on earth with his grandpa gohan just...
No, he didnt die when he fought frieza. After killing frieza he escaped from dying namek on a spaceship but then crashed landed on another planet. After getting healed he then went back to earth.