The E120 is only compatible with Windows 7 32-Bit so ..
As per Lexmark website it states to use the inbuilt drivers in Windows 7 and install the printer.
Follow the steps below to install the inbuilt drivers for Lexmark E120 and check if it installs properly.
Click on Start and click on Control Panel.
Click on Device and printers.
Click on Add Printer.
In the list select Lexmark and the model number on the right pane.
Install Lexmark E120 printer from the list and check if it helps you print.