wireframed models occur when the graphics card you're using doesn't support the texture used on it, which in the cores case is a very detailed, rather epic looking wavey thing.
Same with the flashlight. Graphics card problem.
I had the exact same thing using an integrated card on my old PC. If you have one too, i suggest getting a regular card, and if you have a regular one, it's time for an upgrade.
If you go to Kleiner's lab in HL2, is there a big square on the floor where there should be a puddle of oil? If so you have exactly the same issue i had.