I just got the pc and when i play the game there is you can either say square or dimands with ! marks in the middle there everywere i walk and is realy annoying specialy when i try to play mods because wasteland defence for exanple i try to make the buildings and all it is is a red square box with ! in it.does anyone know how i can fix it or even wats wrong with it?

sounds like some glitch with your graphic card. try downloading and installing the latest drivers or changing the video configs

Nah, it's not a graphic card problem. You need to download archiveinvalidated if you're using mods or else that problem will persist. Also make sure you're installing the textures/meshes etc. in the right place.

I had this problem with a vanilla Fallout 3 install, just after I installed the DLC from disc 2. Something was messed up, but a reinstall (of the DLC) fixed it.

were do i download that?

also were do i put the mesh and sort in the date folder right?

If you haven't installed any mods and the Missing Mesh Markers are everywhere, something is majorly wrong with your game installation. You need to do a file integrity check through Steam to see what's missing or corrupted. Need a walk-thru on how to do that?