Sound problem. im reejay 16, my laptop is hp pavilion zv5202AP. . .whenever i try to watch or

Question

im reejay 16, my laptop is hp pavilion zv5202AP. . .whenever i try to watch or play a song. .i couldnt play it. it appears there that i have no sound card or sound drive installed. i dont know what to do. i tried everything suggested on help and support. i still dont know whats wrong. and im confuse to try the other suggestion because im afraid that it might cause to delete all my files. and ive got my lap top reformated few days ago. and the technician said that i need to download audio sound(forgot it actually). i dont know where to find it. please help me!