Are the Speakers plugged into the computer and into the electricity???
Yeah it's a stupid question to ask, but you'd be surprised... If it is New, why are you on here instead of contacting who you bought it from???
There are too many things that can be wrong with a computer to give any real advice over a question board such as this one...
I mean I can list several things that could be wrong, doesn't mean any of them will be...
Could just be bad luck and you got a lemon {aka bad sound card}... This lemon suggestion could also cover a number of other internal problems that could exist...
Double check the that the speaker wire is plugged into the proper hole, there are usually several to choose from...
Make sure the Speakers are plugged into the Outlet...
Could be that the Speakers are Bad...
I'd take it back to where you got it, if it were me...