Traveller;
Usually when that occurs, it means the system does not detect the device, rendering the software used to scan useless. You did not say what operating system you were running so I'll assume Windows.
Click on My Computer and see if the scanner shows up in the display of your computer components. I'm betting it does not from your desciption. If it ISN'T there, (I'm also assuming that it is a USB connection), ensure that the USB connection is still present (make sure it's plugged in on both sides- scanner and PC). If that was the problem, and you are on Windows 98, NT, 2000 or XP, the plug and play feature shoud re-install your scanner for you.
If that does not work, got to Control Panel and click on the Add New Hardware Icon. Wait for the window to populate and then respond NO to the "Is the hardware already installed?" prompt. Then select the scanner from the subsequent list and try to re-install it that way.
Good luck.