Team Fortress 2 strange graphics?

I got team fortress 2 since it went f2p. When I start the game up it works fine, aside from long load times and, occasionally, trouble connecting to a game.The trouble really starts when i start playing. There is a weird neon orange and green color on objects and on the map that. I can't see my gun clearly and there is a triangle shape in front of me that is the color that my hand should be. Also, when selecting a class, i can only see the gun, not the character. I played around whit the video settings, but nothing i did worked. I can post my specs if i need to, but what i am really wondering is: is this a glitch with the game, or is my video card too weak to hand TF2? Can you run it says that this game should pass on my pc. Also can i even trust can you run it? I can play other games like minecraft and KOTOR (on low settings). Thanks.