If the sound bar is active meaning it has amps to the power the speakers, it will work if you have the correct outputs from PC and inputs to the sound bar. Then depending on what you want and your mobo, it might be a decent solution. A sound bar(or center speaker) either under or over a display is the whole point, for example like a center channel speaker that might offer even more quality sound.
http://www.crutchfield.com/p_760IMG...herry.html?showAll=N&search=image_c4&skipvs=T. Of course you will need an amp to power this speaker.
If you're into watching movies, a center channel speaker is very important. 50-70% of the sound information is directed to the center channel. Even for gaming and music it's a nice addition.
More info is needed: What sound bar(sound bar you already have?) and what motherboard?
Happy listening, the Prisoner...