reverse your speaker wires. Is it now only the right one ? You will then know wether it is the speaker of the computer.

Uninstall your drivers for your soundcard and reinstall them.

Maybe the cable between the speakers and the soundcard has a loose connection, maybe (though very unlikely) it is broken.. check all cable connections and if it still doesnt work, try using a different cable.

___________________
Cybernetika albums (free DL): Atropos (2009) | Nanospheric (2008) | Neural Network Expansion (2007) | Promo #1 (2006) | Paralysis (2005)

homepage: http://www.cybernetika.de

Dud cables are common. I've had my Virus B drop out a channel more than once and yeah, you either swap the wires or use one wire to the left input on the monitor. See if you hear sound from the left speaker. Do the same to the right input. Hear sound?

Then reverse the soundcard outputs and do the same. That way you can tell if its your sound card outs, your cables or your monitors that are fucked. Its mostly the cables though.

That's ironic, I just started having the same problem with my monitors.

Try plugging your speakers into another source and seeing if it still does it when the problem occurs.
The problem with mine persisted when I plugged them into another computer, the other thing I noticed is the speaker the power plugs into is always warm now, whether they're on or off.

I need to get a better set of monitors so I'm not too bothered by it.

___________________
Without music life is a journey through the desert.