You can try the following:
1. Open VLC, Be sure you are in the wxWidgets (this is the default) mode, from the "Settings" pull down check "Extend GUI", on the video tab check "enable" and then "restore defaults". Now try calling a file into VLC. If you have just reset VLC I would not suspect this one.
2. Some games store information by changing settings on your video card so it would be smart to reset your video card to its defaults for 3D, OpenGL and Overlay
3. change resolutions of your video card. If you are at 1024x768 for example go to 800x600.
4. Change color depths of your video card. If you are at 32 bit color try 24 bit or 16 bit.
5. Try shutting off the video acceleration inside VLC. Settings, Preferences, Video, untick the "Overlay video output" box and save. Now close VLC and restart. Then try to call a file, within VLC.
6. As a last resort, try opening VLC Settings, Preferences, Video, Output Modules and using the pull down to select "Windows GDI video output". Then save, restart VLC and try to call a file.