To check your language, close Greenfoot, load up C:\Users\YOURUSERNAME\greenfoot\greenfoot.properties in a text editor. Find the line "bluej.language=" and change it to bluej.language=english , then save the file and load Greenfoot. If the problem still persists, I would try upgrading or reinstalling your graphics card drivers, and/or making sure you are on the latest version of Greenfoot (3.6.0)
i've already editing greenfoot.properties and using 3.6.0 version and the problem still presist. im gonna try upgrading my driver tomorrow.