Scanner not recognized

The scanner is listed under scan but when I click on it I get a message no devices on system. It is not listed on the scanner/dpi

Hello Virginia. When this happens, it's worth trying these:
1) if your PC hasn't been rebooted recently, reboot - some Windows updates cause hardware problems until the first reboot.
2) uninstall and reinstall the scanner's newest driver software, downloaded from the manufacturer's website.

Regards
Zoltán