Half lfie 2 episode 1 wire frame error

i just got half life 2 episode 1 and installed it then started it up and every thing went all right until i got to the first scene in the game were the purple monsters take ALex away from the explosion but after that part of the first scene every thing goes starnge. all the people turn to wire frames, when i saw this i pause the game and went to the start menu and stoped the game.
How do i fix this?
if i enable the developers console and input the codes mat_wireframe 1 or
vcollide_wireframe 1 will this problem go away?
How can i fix this?

oh and it took more than 55 minutes to install this so i would rather not re-install.

Is this a pirated version or was it downloaded from Steam?

i got it from a friends 500gb hard drive.

Any legitimate HL2 game can be fixed through Steam but pirated ones are on their own.