Hi Ulysses,
Please right-click Start, and click Device Manager.
Select a device or a category in Device Manager.
From the Action menu, select Devices and Printers.
If your old printer/scanner is shown in Devices and Printers, right-click it and choose "Remove device".
Also, check if your new printer is shown in that applet.
Once done, open Windows Fax and Scan. From the Tools menu, click Scan Settings. Choose your new scanner.