Lighting Problems and Others

i had just recently reinstalled Gmod after a system refresh. When i was running around in some of the maps, i notice that the lights in just about all of them ( ceiling and electric lights, not natural) had a checkered box in its lighting, and its messing with my pictures. also, when i wrapped up a scene i was working on in a TF2 map and i booted it back up, alot of the props were replaced with errors, mostly the cart tracks! anyone know the problem?

[editline]11th November 2014[/editline]

i figured it out, had to reinstall TF2. could someone close this please