You plug the rca to the rca in of your home theater and the 1/8 plug to the out of your laptop. You'll get more power than plugging the speakers directly in your laptop, but the sound will be stereo, not 5.1
Is that what you were looking for?
im just looking for a home theater system. but i wanna also use the speakers for my laptop and yes i will ahve a external 5.1 sound card for the speakers. and from what your saying is that any system's speakers will work ??
As long as your sound card has enough channels... Or just running 5.1 speakers in stereo Yes, any speakers should work. Eh, though also realize they need to be amplified in some way, but I assume you're either getting a set of computer speakers or say a home theater setup which should have either a reviver or "central" amp.