Provide the following information:
PC Specs, Open run by pressing windows key+R or whichever way you fancy, type msinfo32 , Goto File>Export , Save the file and attach it here.
Secondly Have you updated your graphics drivers?
Last but not the least, Provide game.log of ETS2 by going into Documents/EuroTruckSimulator2 , Open the file and upload to pastebin.com or attach it here.
Awaiting for response.