Windows Vista does not recognize new speakers

[mur123007]

Hello,
I had been using Realtek left and right speakers with sub-woofer. One day the sound went away, on checking I found the sub-woofer was bad. I bought and installed Altec 2.1 speaker system with sub-woofer. Altec Lansing says the speakers need no sound card driver. I don't have any sound, what do I do now?
Thanks

 

[astrallite]

Enable the speakers through the Control Panel -> Hardware and Sound.