Are these speakers usb connected or does it have it's own ac power supply? Next thing to check, and recheck is all connections. If it a usb connection try a different usb port. If ac powered make sure all connections are fully seated. Then the next step would be to check speakers with another pc and if problem persists on other pc you confirmed that the speakers are bad and need to be replaced. If they work then the next step would be to check in device manager for any sound issues, if none are present then uninstall driver from with in device manager and and reboot system. On reboot, the OS will install original sound driver(s). If system has a sound card, check manufacturer and download the most updated driver for that card. Go through all these steps and post back with your results and we can go from there if more help is needed.