How come my computer doesn't have any sound?

if all those didnt work for u i say u shud also try this.... in the task bar i hope u can see a speaker icon on the right side? do u c it? double click it not single but double click it u shud be able to c somethin called "wave" there adjust it to full n then try increasin the volume too that shud fix ur problem for sure i had the same prob but it works for me. even that if didnt work u shud probably do somethin to ur sound card.... jus do this dont mess with any other system files.