Don't have this scanner. But in general when you install a device on windows you need to install the software before you hook the device up to the computer. If you connected the device to the computer before installing the software you should go to control panel, look for scanners and make sure the the scanner is not listed. If it is listed, uninstall it. Then install the software and then connect the scanner.
What version of Windows are you using XP, Vista, Windows 7?
If you have installed the software and then connected the scanner:
Go to control panel and select device manager
click on scanner in Windows7 scanners are under imaging devices
right click on you scanner and then click on properties
What is device status? Should say device is working properly or give you an error messages. You might see a yellow triangle with a message for example
Click on drivers to see if the driver is installed.
Hope this helps