The PWR LED does not light until the drivers are installed. Make sure that the drivers are installed correctly by following the general troubleshooting procedure.
When you insert or remove a USB cable from your computer, the computer should indicate activity such as hard disk activity or an hourglass cursor. If the computer does not show any sign of activity, your system may not be properly communicating with the USB ports. Try these techniques to determine whether the ports are communicating properly:
Try using a different USB port on the computer. If you are using a USB hub, try using a USB port on the computer instead.
If the modem has worked previously and you removed the USB cable from the computer and then reconnected it, try another USB port. The modem may have been installed originally on the other USB port.
Windows Users: Your USB port may not be enabled. To ensure that USB is enabled on your system:
Go to the device manager:
Click Windows Start > Control Panel > System and Maintenance > System.
Under Tasks, click Device Manager.
Click Windows Start > Control Panel.
On the Hardware tab, select Device Manager.
On the desktop, right-click My Computer and select Properties.
On the Hardware tab, click Device Manager.
Look for an entry for USB controllers:
If the device manager does not have an entry for USB controllers, you must enable USB in the computer's BIOS. For instructions, check with your computer manufacturer's technical support. Once your USB port has been enabled in your system's BIOS, Windows will automatically detect and install USB support when you restart your computer.