If windows is telling you "no drivers found for this device", that means that plug and play was unable to detect and install the driver. In any case, I don't know what a lucent 1645 is, but if windows did not identify it automatically as the driver for your modem, then it is not the right one.

Confus-ed makes an important point - you probably spent as much for shipping the driver than a new modem would cost ($15-$20).

Take a look at the first chapter of this http://www.zoomtel.com/documentation...542-3649-b.pdf Its the installation guide for a lucent modem sold by zoom. The key is, you need to install the driver before you install the modem. So, first remove the modem. Next boot into safe mode and follow the steps outlined by platypus to remove the device and driver. Reboot. Install the Agere driver. Shut down. Reinstall the modem. Reboot. Windows should detect the modem and install the driver.