Solidworks 2018 -why display of edges is jagged?

Dell Precision Mobile workstation : 7520

Graphics card : Nvidia quadro M1200

Graphics Driver : Certified for Solidworks 2018

Solidworks 2018 SP4 Installed.

Suddenly since yesterday the display edges and curves has become jagged.What could have happened?what can be done?

Its not a Solidworks issue for sure.

SolidworksGeneral