Below on this Lexmark page, you will find links for downloading C780n Laser driver you need.
A Digimax S700 driver is an important program for your Lexmark laptop or computer, as it promotes correct functioning of your EtherFast Integrated device. Moreover, a driver can promote correct functioning of any other device, e.g., a printer, a scanner or a display card. As a rule, your D910GLDWL unit is already furnished with a CD with the proper C780n Laser driver set. If the CD is lost, please take advantage of the D910GLDWL link for C780n Laser downloading.