How Can I Do A Hardware Reset?

[JPM42]

So I'm a musician and the soundcard that I use to record (which is connected via Firewire) just suddenly stopped working not long after I moved to another house. After checking al the possible remedies, I was suggested that I might have some luck doing a hardware reset. I have an iMac. Does anyone know how this might be done?

Your help is greatly appreciated. Thanks!

 

[spinnerlys]

SMC reset: http://support.apple.com/kb/HT1543

 

[brop52]

SMC: Shut down, unplug everything including the power cord, keyboard, mouse, and anything plugged into it, wait 15 seconds or more, plug it back in and the mouse/keyboard, and last turn it on.

PRAM: Hold down command-option-p-r at startup until it chimes twice and then let go.