Problem Half life 2

[Julio 2395]

hello

I have the steam half life 2 the orange box compradito in me and everything is going well but I have the following problem

the shadows of the characters and some things are totally dark


I mean that which should be the shadow of a character or object is a black box
You can see in my screenshots

I have a Nvidia 6200
and an Intel Pentium IV

any way to fix that?
Thanks in advance :)