Ok. Uninstall ALL the software of your LEXMARK and BROTHER printers, disconnect your printers and reboot the system.
After the system boot again, DON'T CONNECT ANY PRINTER, install the driver and software for the LEXMARK printer, when the installation program show you a message that say connect the printer, in that moment, you must connect the printer.
When the installation program finished, reboot your PC, wait 'till boot again and test the printer.