No more sound

[DietDrThunder]

I turned off my PC, unplugged the speakers that are built into my Asus monitor, and plugged in new Insigna speakers. I can't get any sound out of the speakers (yes they are plugged into power, the power button is on, and the volume is turned to max clockwise). On reboot, Windows 7 recognized speakers were plugged in, and brought up a setup screen. Nothing, no sound. So now I plugged the monitor speakers back in and guess what, no sound. Any suggestions on what to do next?